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EW  QUESTIONS  AND 
iLEMS  IN  CHEMISTRY 


UNIVERSITY  OF  CALIFORNIA 
AT   LOS  ANGELES 


GIFT  OF 

HERMAN   FLECK 


REVIEW  QUESTIONS  AND 
PROBLEMS  IN  CHEMISTRY 


COMPILED  BY 

M.  S.  H.  UNGER,  A.M. 

HEADMASTER  OK  ST.  JOHNS  SCHOOL,  MANL1US,  NEW  YORK 


GINN  AND  COMPANY 

BOSTON  •   NKW   VoKK  •  CHICAGO  •  ]X)NDON 


COPYRIGHT,  1912,  DY 
M.  S.  H.  UNGER 


ALL    RIGHTS   RESERVED 
812.11 


U5/Y 


PREFACE 


The  fact  is  borne  out  by  the  experience  of  every  teacher 
J  who  has  classes  to  prepare  for  college  examinations,  that  the 
^   contents  of  the  prevailing  textbooks  fail  to  furnish  adequate 
%>  scientific  material  and  drill  to  pass  the  entrance  examina- 
tions. The  subject  is  so  broad  and  the  theories  involved  are  so 
\     complex,  that  the  student  often  finds  himself  on  the  thresh- 
N}  old  of  the  examination  room  completely  bewildered  by  the 
'    many  facts,  theories,  laws,  and  details,  and  is  entirely  unable 
,   to  make  a  scientific  application  of  his  knowledge. 

This  book  has  been  prepared  as  a  review  of  the  theories 
N,  and  laws  of  elementary  chemistry,  and  there  has  been  added 
3  to  each  topic  a  sufficient  number  of  problems  to  make  a 
"3  thorough  application  of  the  student's  knowledge.  It  pre- 
^  sumes  on  the  student's  part  a  thorough  acquaintance  with 
\  physical  mixtures,  laws  of  densities  and  specific  gravity,  laws 
^  of  heat  and  electricity,  the  metric  system,  and  an  adequate 
|  training  in  some  good  textbook  in  elementary  chemistry. 

These  questions  and  problems  have  been  taken  from  the 

^>  most  recent  college,  College  Board,  and  Regents  of  the  State 

of  New  York  examinations,  and  from  the  latest  and  most 

^authoritative  textbooks,  and  will  be  found  from  the  author's 

^experience  more  than  sufficient  to  prepare  a  student  for  the 

^entrance  examinations  for  any  college,  or  for  the  College 

x  Board  examinations. 

The  questions  and  problems  are  classified  so  that  a  chapter 
or  parts  of  one  may  be  taken  up,  in  connection  with  the  text- 
book used  in  the  class,  for  clinching  the  principles  studied, 
or  the  book  may  be  used  as  a  pre-examination  review.    It  is 
iii 


iv  REVIEW  QUESTIONS  AND  PROBLEMS 

not  necessary  that  the  student  should  solve  all  the  prob- 
lems, but  such  selection  should  be  made  as  will  assure  the 
instructor  that  he  is  adequately  prepared. 

It  must  be  observed  in  the  use  of  the  book  that  the 
student  must  seek  much  necessary  information  from  his 
text,  and  there  should  be  accessible  several  good  textbooks 
for  handy  reference. 

Eeference  to  the  appendixes  will  be  found  helpful  in 
solving  many  of  the  problems. 

Acknowledgment  is  hereby  made  to  the  authors  and  pub- 
lishers of  the  following  textbooks,  for  the  material  obtained 
from  their  publications :  Lee's  "  Experimental  Chemistry," 
P.  Blakiston's  Son  &  Co. ;  Linebarger's  "  Chemistry,"  Rand, 
McNally  &  Company ;  Newell's  "  Inorganic  Chemistry  " 
and  Baskerville  and  Estabrooke's  "  Problems  in  Chemistry," 
D.  C.  Heath  &  Co. ;  Brownlee  and  Others'  "  First  Principles 
of  Chemistry,"  Allyn  and  Bacon ;  Morgan  and  Ly man's 
"  Chemistry,"  The  Macmillan  Company ;  McPherson  and 
Henderson's  "Elementary  Chemistry"  and  the  publications 
of  the  College  Entrance  Examination  Board,  Ginn  and  Com- 
pany ;  and  to  the  authorities  of  the  various  universities,  and 
to  the  Board  of  Regents  of  the  State  of  New  York,  whose 
entrance  examination  questions  have  been  used. 

MAKLIUB,  NKW  YORK  M-  &  H.  UNGER 


CONTENTS 


CHAPTER 

PAGE 

I. 

PHYSICAL  DEFINITIONS    

1 

II. 

CHEMICAL  DEFINITIONS  

2 

III. 

PHYSICAL  LAWS  AND  THEORY      

4 

IV. 

CHEMICAL  LAWS     

5 

V. 

CHEMICAL  THEORY      

7 

VI. 

CHEMICAL  DIVISION-     

8 

VII. 

El  ECTROLYTIC    DlSSOCI  \TION 

14 

VIII. 

VALENCY   

17 

IX. 

PERIODIC  CLASSIFICATION    

.        18 

X. 

HYDROGEN  AND  WATER      

.       19 

XI. 

THE  NITROGFN  GROUP  AND  AIR 

24 

XII. 

THE  OXYGEN-SULPHUR  GROUP    

.       29 

XIII. 

THE  CVRHON  Sn  ICON  GROUP 

34 

XIV. 

Tin:   HALOGENS  

41 

XV.     TllE    Al.KAI.INE-EARTH     METALS   ......  45 

XVI.    TIIE  ALKALI  METALS       .........  49 

XVII.    Tin:    ALUMINUM-BORON   GROUP    ......  52 

XVIII.    THE  IRON,  NICKEL,  COIIALT,  PLATINUM  GROUP.  55 

XIX.    THE  COPPER,  SILVER,  GOLD  GROUP     ....  57 

XX.    THE  CHROMIUM-MANGANESE  GROUP    ....  60 

XXI.    ORGANIC  ACIDS  AND  COMPOUNDS     .....  62 

XXII.    K(,M  ATID.NS  AND  GENERAL  FORMULAS.     ...  64 

XXI  1  1.    (^  r  LSI  KINS  AND  CALCULATIONS: 

A.  PERCENTAGE  COMPOSITION  ......  74- 

B.  ATOMIC  AND  MOLECULAR  WEIGHTS     .     .  75 

C.  SIMPLEST  FORMULAS  ...     .....  77 

D.  MOLECULAR  FORMULAS  .......  78 

XXIV.    WEIGHTS  AND  VOLUMES  FROM  EQUATIONS  .     .  81 

XXV.    MISCELLANEOUS  QUESTIONS  AND  PROBLEMS.     .  85 
XXVI.    PROP.LEMS    ON    MEASUREMENT,    TEMPERATI  I:K, 

WEIGHT,  AND   DENSITY    ........  !»7 

XXVII.    APPENDIX  .                                                                 ,  103 


REVIEW  QUESTIONS 
AND  PROBLEMS  IN  CHEMISTRY 


CHAPTER  I 
PHYSICAL  DEFINITIONS 

1.  Define  physical  change  and  give  two  examples. 

2.  Define  matter  and  energy,  density,  specific  gravity. 

3.  Define  element,  mixture,  compound,  molecule,  atom, 
electron,  ion,  gas. 

4.  What  are  properties  ?    Mention  those  common  to  all 
matter.    If  we  had  no  senses,   would  we  know  anything 
about  the  properties  of  substances  ? 

5.  What  forms  of  energy  are  possessed  by  a  clock  ?  a 
projectile  ?  a  trolley  car  ? 

6.  When  a  certain  amount  of  water  freezes,  does  it  absorb 
or  give  off  heat  ?    What  difference  in  heat  transfer  takes 
place  when  water  drops  in  temperature  from  2°  to  1°,  and 
from  1°  to  0°  ? 

7.  Give  examples    of  physical  changes  which  are  pro- 
duced through  the  agency  of  heat ;  of  light ;  of  electricity ; 
of  chemical  changes. 

8.  Define  the  difference  between  a  mixture  and  a  com- 
pound, and  illustrate  each. 

9.  Give  examples  of  gaseous  mechanical  mixtures  and 
of  gaseous  chemical  compounds.    Give  similar  examples, 
liquid  and  solid,  and  point  out  the  most  important  differ- 
ence between  compounds  and  mixtures. 

1 


2  REVIEW  QUESTIONS  AND  PROBLEMS 

CHAPTER  II 
CHEMICAL   DEFINITIONS 

1.  How  does  chemistry  differ  from  physics  ?    What  is 
a  chemical  change  ? 

2.  Define    oxidation,    reduction,    kindling    temperature, 
decay. 

3.  How  does  combustion   differ  from  decay  and  from 
oxidation  ? 

4.  What  is  a  formula  ?   a  reaction  ?  an   equation  ?   a 
radical  ? 

5.  What  is  a  flame  ?    What  causes  luminosity  ?    Why  is 
a  Bunsen  flame  nonluminous  ? 

6.  Define  catalysis,  molecule,  electrolyte,  nascent  state, 
allotropy. 

7.  Define  deliquescence,  efflorescence,  electrolysis,  and 
illustrate  each. 

8.  Define   chemism,   vapor  density,   isomerism,  polym- 
erism,  absolute  temperature. 

9.  Define  hydroxide,  alkali,  metathetic  reaction,  solution. 

10.  Distinguish  between  crystals  and  water  of  crystalli- 
zation ;  between  colloids  and  crystalloids ;  between  crystal- 
line and  amorphous. 

11.  Explain  and  illustrate  deflagration,  supersaturation, 
fusion,  sublimation. 

12.  What  is  meant  by  bivalent,  monatomic,  diatomic  ? 

13.  State  the  meaning  of  distillation,  filtrate,  titration, 
standard  solution,  indicator,  neutral  reaction. 

14.  Define  the  following  terms:  atom,  valence,  equivalent, 
gram  molecule,  fermentation,.precipitation. 


CHEMICAL  DEFINITIONS  3 

15.  Give  three  methods  for  collecting  gases,  and  the  con- 
ditions under  which  each  may  be  advantageously  employed. 

1 6.  To  what  classes  of  changes  do  the  following  belong : 
(<y)  the  melting  of  ice  ?  (//)  souring  of  milk  ?  (c)  explosion 
of  gunpowder?  (rl)  corrosion  of  metals?  (e)  burning  of  a 
candle  ?    (/)  ringing  of  a  bell  ?    (f/)  stretching  of  rubber  ? 
(7i)  boiling  of  an  egg  ?  (i)  dissolving  of  sugar  ?  (j)  decay 
of  meat  ?  (k)  magnetizing  of  a  nail  ? 

17.  What  is  the  property  that  distinguishes  compounds 
from  mixtures  ?   What  is  an  element  ?    What  conditions 
must  be  taken  into  account  in  measuring  the  volumes  of 
gases  ?    By  what  instruments   are  these  conditions   meas- 
ured '.'    (Jive   the   laws   which  express  the  effect   of  these 
conditions. 

18.  Distinguish  between  chemical  and  physical  properties ; 
between  elements,  compounds,  and  mechanical  mixtures ; 
between  metals  and  nonmetals ;  between  gases,  liquids,  and 
solids  ;  between  oxidation  and  reduction. 

19.  In  the  measurement  of  volumes  of  gases  what  do  you 
mean  by  standard  conditions  ?   Should  you  consider  it  neces- 
sary to  make  use  of  such  conditions  in  measuring  volumes 
of  liquids  or  solids  ?    Why  ? 

20.  Describe  two  ways  in  which  well-formed  crystals  are 
obtained.    How  should  you  distinguish  a  crystalline  from  an 
amorphous  body  ? 

21.  Explain  the  object  of  each  of  the  following  processes 
and  how  each  accomplishes  the  end  in  view :  (a)  evapora- 
tion of  a  solution  of  a  solid ;  (b)  filtration  ;  (<•)  distillation ; 
((/)  pulverization  before  dissolving ;  (e)  sublimation. 

22.  Name  two  forms  of  energy  that  may  produce  chemical 
changes,  and  give  an  example  of  a  change  caused  by  each. 

23.  Define  each  of  the  following  and  give  an  example  of 
each  :  («)  monobasic  acid ;  (lij  dibasic  acid ;  (c)  tribasic  acid, 


4  REVIEW  QUESTIONS  AND  PROBLEMS 

and  write  the  name  and  the  formula  of  a  salt  formed  from 
each  of  the  acids  mentioned. 

24.  Define    spontaneous    combustion    and    explain    the 
phenomenon. 

25.  Define  and  illustrate  molecular  weight,  anhydride, 
deliquescence,  antiseptic,  precipitate,  monad,  occlusion. 

26.  Define   and   illustrate   the   following :    binary   com- 
pounds, hydrate,  base,  dyad,  compound  radical,  metal,  neg- 
ative element. 

27.  Define  chemical  change ;  classify  the  different  kinds 
of  chemical  change,  and  give  an  example  of  each. 

28.  Define  basic  anhydride,  acid  anhydride,  and  give  an 
example  of  each.    What  is  a  dibasic  acid  ? 


CHAPTER  III 
PHYSICAL  LAWS  AND  THEORY 

1.  State  and  illustrate  the  relation  that  exists  between 
centigrade,  Fahrenheit,  and  absolute-temperature  scales. 

2.  State  the  formulas  for  converting  temperatures. 

3.  Explain  the  meaning  of  the    following    statement : 
"  A  gas  is  under  standard  conditions  of  temperature  and 
pressure." 

4.  State  (a)  Boyle's  (Mariotte's)  Law;  (ft)  the  Law  of 
Charles. 

5.  Distinguish  between  and  illustrate  (a)  law,  (ft)  theory, 
(c)  hypothesis. 

6.  What    is    (a)    occlusion  ?    (ft)    diffusion    of    gases  ? 
(c)  spectrum  analysis  ? 

7.  What  is.  the  kinetic  theory  of  matter  ? 


CHEMICAL  LAWS  5 

8.  Define  specific  gravity  or  relative  density,  and  show 
how  you  would  determine  the  specific  gravity  of  a  gas,  a 
liquid,  and  a  solid.    If  the  specific  gravity  of  marble  is  2.75, 
how  much  in  grams  would  a  cubic  meter  of  marble  weigh  ? 

9.  Explain  in  terms  of  the  kinetic  molecular  theory  the 
difference  between  solids,  liquids,  and  gases. 


CHAPTER  IV 
CHEMICAL  LAWS 

1.  State  and  illustrate  the  Law  of  Definite  Proportions. 

2.  State  and  illustrate  the  Law  of  Multiple  Proportions. 

3.  State  the  Law  of  Dulong  and  Petit.   What   use  is 
made  of  it  by  chemists  ? 

4.  State  the  Periodic  Law.    What  three  striking  predic- 
tions made  by  Mendeleeff  have  since  been  verified  ? 

5.  What  is  the  basis  of  the  Mendeleeff  classification? 
What  evidence  have  we  that  this  is  a  natural  system  ?  Dis- 
cuss the  properties  of  the  elements  in  some  natural  family 
in  such  a  way  as  to  show  this  apparent  relation. 

6.  Give  the  law  for   the   conservation    of   matter;   of 
energy. 

7.  Give  Hess's  Law  of  Constant  Heat  Summation. 

8.  State  the  Law  of  Electrochemical  Equivalents;  the 
Law  of  Equivalent  Proportions. 

9.  State  Graham's  Law  of  Diffusion  and  Transpiration. 

10.  State  the  Law  of  Dal  ton  for  a  gaseous  mixture. 

11.  What  is  the  Law  of  Gay-Lussac  ?    Illustrate. 

12.  State  Faraday's  Laws  of  Electrolysis. 


6  REVIEW  QUESTIONS  AND  PROBLEMS 

13.  Name  four  agencies  that  may  bring  about  a  chemical 
change,  and  illustrate. 

14.  State  the  Law  of  Specific  Heats.    Illustrate  its  use  by 
an  example. 

15.  What  are  Berthollet's  Laws  ? 

16.  What  distinction  would  you  make  between  a  law  and 
a  theory  ?    Give  an  illustration  of  each  and  tell  why  it  is 
thus  classified. 

17.  The  formulas  of  the  five  oxids  of  nitrogen  are  N2O, 
NO,  N203,  N204,  and  N2Og.  What  simple  ratio  exists  between 
the  varying  weights  of  oxygen  ? 

18.  State  and  illustrate  Ampere's  Law.  Mention  a  method 
of  finding  the  molecular  weight  of  a  given  compound  when 
its  atomic  weights  are  not  known. 

19.  State  what  is  meant  by  saying  that  the  vapor  density 
of  a  gas  is  44. 

20.  State  Boyle's  Law   and   Charles's   Law.    A   certain 
quantity  of  a  gas  occupies  1 1.  at  0°  C.  and  760  mm.  Calculate 
its  volume  at  20°  C.  and  750  mm. 

21.  State   Avogadro's  Law;  also  the  Law  of  Multiple 
Proportions.    What   volume    of   carbon    dioxide    would    be 
formed  if  1  1.  of  acetylene  (O^L^)  burned  in  oxygen  with 
the  formation  of  C02  and  H2O  ? 

22.  What  is  the  law  governing  the  combination  of  gases 
by  volume  ?  Give  some  examples  illustrating  the  law.   What 
is  the  hypothesis  advanced  to  explain  it?   Show  how  this 
hypothesis  gives  rise  to  a  method  of  expressing  the  weights 
of  molecules. 

23.  What  evidence  have  we  that  matter  is  indestructible  ? 
If  we  cannot  create  matter,  how  are  we  to  account  for  the 
fact  that  the  products  of  combustion  of  a  candle  weigh  more 
than  the  original  caudle  ? 


CHEMICAL  THEORY  7 

24.  Give  and  illustrate  two  laws  that  lie  at  the  founda- 
tion of  clicniica.1  knowledge.    What  law  gives  the  basis  for 
calculating  molecular  weight  ? 

25.  Give  the  characteristics  of  a  chemical  change,  and 
two  important  laws  governing  chemical  change. 

CHAPTER  V 
CHEMICAL  THEORY 

1.  State  the  principle  of  Dal  ton's  Atomic  Theory. 

2.  State  the  theory  of  Avogadro,  and  illustrate  it  by 
the  union  of  oxygen  and  hydrogen  to  form  water,  and  of 
hydrogen  and  chlorine  to  form  hydrochloric  acid. 

3.  Explain  the  theory  of  electrolytic  dissociation. 

4.  Show  how  Avogadro's  theory  is  used  for  determining 
molecular  and  atomic  weights. 

5.  Employ  the  Avogadro  theory  in  calculating  the  atomic 
weight  of  oxygen  from  the  following  data :  carbonic,  acid 
gas,  steam,  laughing  gas,  and  sulphurous  anhydride  contain, 
in  the  order  named,  72.73,  88.89,  36.364,  and  50.00  per  cent 
by  weight  of  oxygen  ;  their  densities  are,  in  the  same  order, 
22,  9,  22,  and  32. 

6.  Tell  what  substance  and  how  much  of  it,  in  terms  of 
the  atomic-molecular  theory,  is  represented  by  each  of  the 
following  symbols  and  formulas  :  HC1,  Ba,  Fe,  P205,  O2,  Og, 
KOH,  Zn(N08)2,  I,  SiOa. 

7.  State  Gay-hussar's  Law  of  the  combining  volumes  of 
gases  and  show  how  it  led  to  Avogadro's  hypothesis. 

8.  What  is  meant  by  (V/)  the  molecular  weight  of  a  gas, 
and  (/>)  the  density  of  a  gas  ?   What  relation  exists  between 
the  molecular  weights  and  the  densities  of  gases  ?  Illustrate. 


8  REVIEW  QUESTIONS  AND  PROBLEMS 

9.  What  evidence  have  we  that  one  element  can  change 
into  another,  and  what  explanation  is  offered  ? 

10.  State  the  Law  of  (a)  Definite  Proportions  ;  (ft)  Mul- 
tiple  Proportions.      Show  how   the   atomic   hypothesis    is 
developed  from  these  laws. 

11.  State  Avogadro's  hypothesis.    Show  how  the  molec- 
ular weight  of  a  given  substance  that  can  be  volatilized  may 
be  found  by  this  hypothesis. 


CHAPTER  VI 
CHEMICAL  DIVISION 

1.  Define  an  acid,  a  base,  and  a  salt,  and  give  an  example 
of  each. 

2.  Give  the  names  of  the  following  acids,  and  of  the 
potassium  salt  of  each :  HC1,  HC10,  HC1O4,  HC103,  HN02, 
HN08,  H2S04,  HBr,  H8As04,  HF. 

3.  What  is  a  formula,  a  chemical  equation,  a  reaction,  a 
graphic  equation  ?    Illustrate. 

4.  Illustrate  an  endothermic  and  an  exothermic  reaction. 

5.  Illustrate  and  explain  the  difference  between  ana- 
lytic, synthetic,  and  metathetic  reaction. 

6.  Define  and  illustrate  neutralization,  normal  salt,  acid 
salt,  basic  salt,  an  anhydride. 

7.  Give  an  example  of  a  dibasic  acid.    Of  H2S04  acting 
(a)  as  an  acid ;  (ft)  as  a  drying  agent ;  (c)  as  a  strong  acid 
displacing  a  weaker  one  (equation). 

8.  Classify  as  (a)  bases ;  (ft)  acids ;  (r)  salts :   NaNO,, 
NH4C1,  HC10,  NH4OH,  BaS04,  Ca  (NO,)  2,  HC104,  Sr(OH)2, 
HN02,  Fe(OH)8. 


CIIK.MK  AL    DIVISION'  9 

9.  Write  the  formulas  for  the  following  compounds: 

barium  perclilorate.  ammonium  sulphate,  strontium  nitrate, 
calcium  sulphate,  ferric  sulphate,  sodium  perchlorate,  cal- 
cium hypochlorite,  barium  hydroxide,  strontium  oxide, 
barium  nitrate. 

10.  What  is  a  primary  salt?    Write  the  formulas  for 
primary    sodium    sulphate,     primary    calcium    phosphate, 
secondary  sodium  carbonate. 

11.  How  may  hydrochloric  acid  be  prepared?    State  the 
properties  of  this  acid. 

12.  Write  the  formulas  for  limestone,  secondary  sodium 
phosphate,  cupric  sulphate,  ammonia,  aluminum  phosphate, 
mercurous    chloride,    barium    nitrate,    acetylene,    gypsum, 
marsh  gas. 

13.  Write  the  formulas  for  sodium  carbonate,  lead  sul- 
phate, silica,  arsine,  arsenic  trioxide,  ammonium  sulphide, 
normal  calcium  phosphate. 

14.  Write  the  formulas  for  potassium  chloride,  sodium 
carbonate,  phosphoric  acid,  sodium   cyanide,  ferric  oxide, 
ferrous  sulphide,  ferric  chloride,  aluminum  sulphate,  cuprous 
oxide,  manganese  dioxide. 

15.  Write  the  equation  for  the  reactions  that  occur  between 

1.  Potassium  hydroxide  and  sulphuric  acid. 

2.  Calcium  hydroxide  and  ammonium  sulphate. 

3.  Ferric  chloride  and  ammonium  hydroxide. 

4.  Sodium  hydroxide  and  phosphoric  acid. 

5.  Ammonium  nitrate  with  heat. 


17.  Write  the  equations  for  the  reactions  between 

1.  Calcium  carbonate  and  hydrochloric  acid. 

2.  Potassium  nitrate  and  sulphuric;  acid. 


10  REVIEW  QUESTIONS  AND  PROBLEMS 

3.  Copper  and  water  vapor  (heated). 

4.  Aluminum  sulphate  and  ammonium  hydroxide. 

5.  Calcium  carbide  and  water. 

18.  Write  the  equations  for  the  reactions  : 

1.  Silver  nitrate  and  sodium  chloride. 

2.  Aluminum  sulphate  and  potassium  hydroxide. 

3.  Ammonium  sulphate  and  slaked  lime. 

4.  Sodium  chloride,  manganese  dioxide,  and  sulphuric 

acid. 

5.  Chlorine  and  potassium  bromide. 

6.  Steam  and  incandescent  coke. 

7.  Calcium  hydroxide  and  carbon  dioxide. 

8.  Methane  and  oxygen  (ignited). 

19.  What  is  meant  by  the  terms  "  saturated  solution  "  and 
"  supersaturated   solution "  ?    Under  what  conditions   will 
crystalline  sodium  sulphate  effloresce  ? 

20.  For  what  do  the   following   symbols   and  formulas 
stand  :  S02,  C,  CH4,  FeO,  Fe208,  CO2,  CaC08,  Hg,  I,,  H3P04, 
NaOH,  NH4,  NH3,  Ag,  Al,  08,  S6,  AsOg,  SnO2,  and  Pb(OH)2. 

21.  Define  basic  anhydride  and  acid  anhydride,  and  give 
an  example  of  each. 

22.  Classify  the  following  substances  as  (")  acids,  (/>)  bases, 
or  (e)  salts,  and  give  the  name  of  each :  H2S04,  KC1,  KHS04, 
NH4OC1,  NaOH,  CaF2,  HI,  Ca(C103)2,  NaN03. 

23.  To  what  extent  does  the  composition  of  a  pure  chemi- 
cal  compound  vary  ?    Take  as  an  example   pure   sodium 
chloride  from  various  sources,  and  mention  other  examples 
if  possible. 

24.  Give   chemical    names    and   molecular  formulas   for 
the  following  substances  :  borax,  Epsom  salts,  Glauber  salts, 
white  vitriol,  green  vitriol,  blue  vitriol,  iron  pyrites,  hematite, 
magnetite,  potash,  galena,  alum,  gypsum,  cryolite. 


<  IIKMICAL  DIVISION  11 

25.   Complete  and  balance  :  •» 


2.  A1(OH)3 

3.  A.1(OH)8 

4.  AgNO,  + 

5.  CaC08  +  C02  +  H/)  = 

26.  Complete  the  following,  using  symbols  and  formulas  : 

1.  Ammonium  hydroxide  +  hydrochloric  acid  = 

2.  Ammonia  +  hydrochloric  acid  = 

3.  Sodium  chloride  +  silver  nitrate  = 

4.  Ferrous  sulphide  +  sulphuric  acid  = 

5.  Lead  nitrate  +  hydrogen  sulphide  = 

6.  Manganese  dioxide  4-  hydrochloric  acid  = 

7.  Calcium  carbide  +  water  = 

8.  Arsenic  trioxide  +  nascent  hydrogen  = 

9.  Sodium  carbonate  +  nitric  acid  = 

10.  Calcium  hydroxide  +  carbon  dioxide  = 

27.  Explain  the  terms   "ion"  and  "  ionization."    What 
classes  of  substances  are  ionized  when  dissolved  in  water  ? 
I  '>  y   what   term  are  all  such  substances  designated  ?    De- 
tiiit1  acid  and  base  in  terms  of  the  theory  of  electrolytic 

dissociation. 

28.  Explain  by  the  ion  theory  the  action  of  hydrochloric 
;icid  on  potassium  hydroxide  iii  dilute  solution. 

29.  Classify  the  given  compounds  under  the  following 
headings:   (")  acids;  (7>)  bases;  (V)  normal  salts;  (V)  acid 
salts;    (,<)    anhydrides;    (/)    oxides:    CO.,,    NaHSO4,   CaCl2, 
1'bO,   II:JP04,  Ca(OH)2,  Na.2S08,  Mi,o.,.~SO,,  NaOCl. 

30.  Write  the  chemical  name  ol  each  of  the  following: 

white  lead,  blue  \itriol,  calomel,  gypsum,  saltpeter,  caustic 
potash,  copperas. 


12  REVIEW  QUESTIONS  AND  PROBLEMS 

31.  Distinguish  in  meaning  between  the  following  suffixes 
when  used  in  names  of  chemical  compounds  :  (V/)  <ms  and  ic ; 
(f>)  ite  and  ate.    (c)  When  are  hypo  and  per  prefixed  ? 

32.  Define  each :  (a)  monobasic  acid ;  (b)  dibasic  acid ; 
(V)  tribasic  acid.    Write  the  name  and  the  formula  of  a  salt 
formed  from  each  of  the  acids  mentioned. 

33.  Find  the  percentage  composition  of  HNOg.    Describe 
a  method  -of  preparing   nitric  acid,  writing  the  reaction. 
Mention  its  uses. 

34.  What  substances  do  you  employ  in  the  laboratory 
preparation  of  hydrochloric  acid  ?    Why  was  each  substance 
selected  ?    Give  the  reason  for  the  method  used. 

35.  Write  the  chemical  name  of  each  of  the  following : 
H2S08,  NaHC08,  H2S,  Fe  (S04)3,  P205. 

36.  Complete  the  following  equations,  using  formulas  : 

1.  Sodium  hydroxide  +  carbon  dioxide  = 

2.  Lead  nitrate  +  hydrogen  sulphide  = 

3.  Calcium  hydroxide  +  nitric  acid  = 

4.  Phosphorus  +  oxygen  = 

5.  Sodium  carbonate  +  calcium  chloride  = 

6.  Hydrogen  +  (hot)  copper  oxide  = 

State  which  of  these  compounds  are  (</)  acids ;  (7;)  bases  ; 
(r)  salts  ;  (rf)  anhydrides.  Which  of  the  equations  are  exam- 
ples of  (e)  oxidation  ?  (/)  reduction  ?  (^/)  double  decom- 
position ?  (//,)  neutralization  ? 

37.  State  how  you  could  distinguish  between 

1.  Concentrated  and  dilute  sulphuric  acid. 

2.  Sodium  chloride  and  sodium  sulphate. 

3.  Copper  sulphate  and  potassium  sulphate. 

4.  Platinum  and  magnesium. 

5.  Pulverized  charcoal  and  manganese  dioxide. 

6.  Hydrogen  and  carbon  monoxide. 


CHEMICAL  DIVISION  13 

38.  What  determines  whether  a  gas  should  be  collected 
(a)  over  water  ?    (ft)   by  downward  displacement  of  air  ? 
(<•)  by  upward  displacement  of  air  ?    State  the  method  used 
in  collecting  ammonia,  hydrogen  sulphide,  carbon  dioxide, 
nitric  oxide. 

39.  Describe  two  ways  in  which  well-formed  crystals  are 
obtained.    How  should  you  distinguish  a  crystalline  from 
an  amorphous  body  ? 

40.  Explain  each  of  the  following  processes,  and  state 
how  each  accomplishes  the  end  in  view :  («.)  evaporation  of 
a  solution  of  a  solid ;  (It)  filtration  ;  (<••)  distillation  ;  (<I)  pul- 
verization before  dissolving ;  (e)  sublimation. 

41.  Describe  experiments  by  which  you  could  determine 
whether 

1.  An  alloy  contained  copper  or  silver. 

2.  A  washing  powder  contained  sodium  carbonate. 

3.  A  sample  of  potassium  chlorate  contained  potas- 

sium chloride. 

4.  A  sample  of  material  contained  sand  or  lime. 

5.  A  gas  was  nitrogen  or  carbon  dioxide. 

42.  Distinguish  between  organic  and  inorganic  chemistry  ; 

between  metals  and  nonmetals. 

43.  Name  the  following  acids  and  write  the  formula  and 
name  Ihe  sodium  salt  for  each: 

HI  HNO3  H8PO2  H2S04 

HIO,         UNO,  H8P08  H2S08 

HI04         HNO  H8P04  HaSaO8 

44.  When   perfectly  dry  sulphuric   acid  is  treated  with 
perfectly  dry  sodium  hydroxide,  no  chemical  action  takes 
place.    Why? 

45.  What  is  a  radical  '.'    (Jive  six  examples. 


14  REVIEW  QUESTIONS  AND  PROBLEMS 

46.  What   are   the   main   points  of  difference  between 
metals  and  nonmetals  in  the  free  state  ?    What  chemical 
property  differentiates  them  as  a  rule  ?  Name  some  elements 
which  have  properties  of  both. 

47.  Define  acid  and  base.   What  is  the  important  theo- 
retical conception  concerning  solutions  ?   What  is  the  mean- 
ing of  the  terms  "  weak  "  and  "  strong  "  as  applied  to  these 
substances  ?   Define  hydrolysis. 

48.  State  the  differences  between  the  solutions  obtained 
by  passing  dry  ammonia  gas  into  water  and  sulphur  dioxide 
into  water.    What  is  the  result  if  each  solution  is  evaporated 
separately?    Explain.    What  is  obtained  when  the  solutions 
are  mixed  and  evaporated  to  dryness  ? 

49.  What  weight  of  Ca(OH).2  can  be  prepared  from  1  kg. 
of  quick  lime,  and  what  weight  of  HC1  will  be  neutralized 
by  the  Ca(OH)2  thus  made  ? 


CHAPTER  VII 
ELECTROLYTIC  DISSOCIATION 

1.  Describe  in  full  what  happens  when  a  solution  of 
sodium  sulphate  is  electrolyzed. 

2.  Describe  in  detail  what  takes  place  when  an  electric 
current  is  passed  through  water  that  has  been  acidulated 
with  sulphuric  acid. 

3.  Explain  what  takes  place  when  a  solution  of  copper 
sulphate  is  electrolyzed  with  a  copper  cathode  and  ;i  copper 
anode.    What  commercial  use  is  made  of  this  process  ?    If 
both  terminals  were  platinum. 

4.  Explain  the  terms  "ion"  and  "  ioni/ation."     What 
classes  of  sul (stances  are  ioni/.ed  when  dissolved  in  water? 


ELECTROLYTIC  DISSOCIATION  15 

1 5 y  what  term  arc  all  such  substances  designated  ?  Define  acid 
and  base  in  terms  of  the  theory  of  electrolytic  dissociation. 

5.  Explain  by  the  ion  theory  the  action  of  hydrochloric 
acid  on  potassium  hydroxide  in  dilute  solution. 

6.  How  would  you  determine  whether  a  given  solution 
is  an  electrolyte  ? 

7.  To  bring  about  a  reaction  between  dry  substances, 
why  is  it  necessary  to  place  them  in  water? 

8.  Distinguish  carefully  between  an  ion  of  sodium  and 
an  atom  of  sodium. 

9.  Explain  the  fact  that  sulphuric  acid  is  less  active 
than  nitric  acid. 

10.  Give  the  conditions  under  which  a  reaction  goes  on 
to  completion. 

11.  If  a  certain  current  of  electricity  deposits  31.7  g.  of 
copper,   (« )  how  much   silver   would  it  deposit  ?    (/>)  how 
much  zinc? 

12.  From  the  standpoint  of  the  theory  of  electrolytic  disso- 
ciation («)  write  the  simple  equation  for  a  dilute  solution  of 
copper  sulphate ;  this  is  a  blue  solution,   (i)  In  the  same  man- 
ner write  one  for  sodium  sulphate ;  this  is  a  colorless  solu- 
tion.   How  would  you  account  for  the  color  in  the  first  case  ? 

13.  Why  will  vegetables  cook  faster  when  boiled  in  strong 
salt  water  than  when  boiled  in  pure  water  ? 

14.  Write  equations  showing  how  the  following  substances 
ionize:  HC1;  HNOg;  NaOH;  Ca(OH)2;  ZuS04;  Fe(NO8)a. 

15.  Write  ionic  equations  for  the  interactions  of  the  fol- 
lowing substances.    Do  the  reactions  run  to  equilibrium  or 
to  completion  ?   Why  in  each  case  ? 

1.  NaOH  +  HC1  -  4.  BaCl2  +  Na2S04  - 

2.  Na3COs  +  HN03  -  5.  Ca  (OH)2  +  H2SO4  - 

3.  Ca(OH)2  +  HC1  -  6.  AgNO,  +  HC1  - 


16  REVIEW  QUESTIONS  AND  PROBLEMS 

16.  Why  do  less  volatile  acids  decompose  the  salts  of 
more  volatile  acids  and  liberate  the  latter? 

17.  Why  does  liquid  chlorine  possess  no  acid  properties  ? 
Would  you  expect  it  to  conduct  an  electric  current  ? 

18.  Salt   dissolved   in  pure  water  conducts  electricity; 
sugar  does  not.    Explain  according  to  modern  views. 

19.  Describe   the   changes  undergone  by  a  solution  of 
sodium  sulphate  (colored  with  litmus)  when  subjected  to 
the  action  of  a  current  of  electricity.    How  may  the  direc- 
tion of  the  current  be  determined  ? 

20.  Define  the  term  "  electrolysis."    Explain  briefly  by 
means  of  a  diagram  what  takes  place  when  an  electric  current 
is  passed  through  a  solution  of  common  salt. 

21.  Define  dissociation.   Describe  a  laboratory  experiment 
to  illustrate  the  dissociation  of  a  chemical  compound  by  the 
aid  of  electricity. 

22.  What  important  difference  is  there  between  the  be- 
havior  of   table   salt   and   that   of   sugar  when  dissolved 
in   water  ?    How   may  the   peculiar   behavior   of   salt   be 
shown?    Name  some  of  the  substances  which  behave  in 
this  manner. 

23.  Define  an  ion  and  an  electrolyte. 

24.  A  current  deposits  1  g.  of  sodium ;  find  the  weight 
of  Ni  deposited  by  the  same  current. 

25.  How  many  grams  of  Ag  will  be  deposited  from  a  solu- 
tion of  AgN08  by  a  current  of  2  amperes  in  30  minutes  ? 

26.  How  much  would  a  metal  plate  increase  in  weight  if 
it  were  nickel-plated  by  a  current  of  0.5  ampere  running 
5  hours  ? 

27.  If  the  specific  resistance  of  Ca  is  0.000001629,  what 
is  the  resistance  of  a  wire  200  in.  long  having  a  cross  section 
of  2  mm.2  ? 


VALENCY  17 

28.  Gladstone  and  Hibbert  on  passing  the  same  electric 
current  through  solutions  of  zinc  and  silver  obtained  quan- 
tities of  the  metals  in  the  ratio  of  (Zn)  1 :  (Ag)  3.298.    If 
the  equivalent  of  silver  is  197.94,  what  is  that  of  zinc  ? 

29.  When  sulphuretted  hydrogen  is  added  to  a  solution 
of  ZnS04,  why  is  the  zinc  not  completely  precipitated  as 
sulphide  ?    How  may  the  precipitation  be  made  approxi- 
mately complete?    Explain  by  means  of  the  hypothesis  of 
electrolytic  dissociation  and  the  law  of  mass  action. 


CHAPTER  VIII 
VALENCY 

1.  For  what  do  the  following  symbols  and   formulas 
sfciml:    S02,  C,  CH4,   Fe203,  C02,  CaC08,  Hg,  I2,  HgP04, 
Nat  HI,  (OH),  (NHJ,  NH8,  Ag,  Al,  08,  S6,  As208,  Sn02,  and 
Pb(OH)2? 

2.  Complete  and  balance : 

1.  NaOH  +  H2S04  = 

2.  Mg  +  HCl  = 

3.  Na  +  H2O  = 

4.  NaN08+NH4Cl  +  H.E.= 

5.  NaCl  +  Mn02  +  H2S04  +  H.E.= 
NOTE.    H.E.  stands  for  heat  energy. 

3.  What  is  meant  by  saying  that  a  chemical  equation 
" balances"  ?    Why  is  it  incorrect  if  it  does  not  "  balance" ? 

4.  AVhat  is  valence  ?  What  is  the  valence  of  iron  in  Fe08, 
and  of  silicon  in  SiH4?    What  is  meant  by  saying  that  an 
element  occurs  in  different  allotropic  forms  ? 

5.  Define  valence.    State  and  illustrate  the  theory  of 
valence. 


18  REVIEW  QUESTIONS  AND  PROBLEMS 

6.  If  1 1.  of  bromine  vapor  weighs  7.2  g.  and  if  1  g.  of  H 
combines  with   80  g.  of  bromine,  what  is  the  valency  of 
bromine  ? 

7.  The  valency  of  the  following  elements  is  indicated  by 
the  number  of  accents :  Na',  K',  Ca",  Al'".    What  are  the 
formulas  of  the  chlorides  and  the  oxides  of  each  of  the 
elements  if  Cl  is  univalent  and  0  is  bivalent? 

8.  How  many  liters  of  hydrogen  gas  can  be  obtained 
from  4  1.  of  HC1  acid  gas  ? 


CHAPTER  IX 

PERIODIC   LAW  AND  THE   CLASSIFICATION  OF  THE 
ELEMENTS 

1.  State  the  Periodic  Law.    What  three  striking  predic- 
tions made  by  Mendeleeff  have  since  been  verified  ? 

2.  Discuss   the   periodic   classification    of  the  elements. 
What  evidence  have  we  that  this  is  a  natural  system  ?  -Dis- 
cuss the  properties  of  the  elements  in  some  natural  family 
in  such  a  way  as  to  show  their  apparent  relation. 

3.  Name  the  important  services  the  law  (periodic)  lias 
rendered  to  chemistry. 

4.  What  property  of  an  element  determines  its  position 
in  the  periodic. arrangement  of  the  elements? 

5.  Arrange  the  following  elements  in  groups  according 
to   some    natural    classification :    aluminum,    barium,   iron, 
phosphorus,  silicon,  sodium,  sulphur. 

6.  What  is  the  difference  between  the  Periodic  Law  and 
the  Periodic  System  ? 

7.  State  the  characteristics  of  the  alkali  group;  of  the 
halogen  group;    of  the  carbon  group;  of  the  argon  group. 


HYDROGEN  AM)  WATER  19 

8.  If  lead  is  an  element  and  radium  is  an  element,  what 
is  tin-  most  significant  difference  between  them? 

9.  What  reasons  are  there  for  thinking  that  there  may 
be  only  one  form  of  matter  ? 

10.  Suppose  that  an  element  were  discovered  that  filled 
the  blank  in  Group  VI,  Period  9,  Family  13  (see  Appendix), 
what  properties  would  it  have  ? 


CHAPTER  X 

HYDROGEN  AM)   WATER 

1.  (u)  Give  two  physical  and  two  chemical  properties  of 
JL.    (//)  Name  two  metals  which  displace  H  from  dilute  HC1, 
and  two  that  do  not. 

2.  State  (Jay-hussar's  Law  of  Volumes  and  illustrate  it 
by  a  consideration  of  the  union  of  H  and  Cl.    Show  by 
Avogadro's  theory  and  the  foregoing  law  that  a  molecule 
of  II  contains  at  least  two  atoms. 

3.  What  volume  of  H  measured  under  standard  con- 
ditions is  required  to  reduce  11.94  g.  of  CuO  ?    What  is 
the  weight  and  what   the  volume   of  the   water  (liquid) 
formed  '.' 

4.  ->  H2  +  Oa=  2H20.    What  does  this  equation  signify 
in  regard  to  (<y)  molecules,  (ft)  the  weights,  and  (c)  the  gas 
volumes  of  the  reacting  substances  and  of  the  product  ? 

5.  How  many  grams  of  the  metal  Zn  are  necessary  for 
the  production,  by  the  action  of  hydrochloric  acid  on  the 
metal,  of  90  1.  of  H  measured  under  standard  conditions  ? 

6.  30  cc.  of  H  is  mixed  with  40  cc.  of  air  that  contains 
20  per  cent  of  (),  and  the  mixture  is  ignited.    What  gases 
remain  after  explosion  and  what  is  the  volume  of  each? 


20  REVIEW  QUESTIONS  AXD  PROBLEMS 

7.  When  H  and  0  unite,  state  the  relation  of  the  volume 
of  steam  produced  to  the  volumes  of  H  and  0  used.    State 
the  law  thus  illustrated. 

8.  A  tube  containing  copper  oxide  (CuO)  weighs  with 
its  contents  63  g.    This  tube  is  heated  to  redness  and  H 
passed  through  it.    When  cooled  the  tube  with  its  contents 
is  again  weighed,  and  the  weight  is  now  found  to  be  60  g. 
\Vhat  volume  of  H  measured  under  standard  conditions  has 
united  with  the  0  of  the  copper  oxide  ? 

9.  How  may  water  be  freed  (a)   from  insoluble  solid 
matter  ?  (U)  dissolved  salts  ?    (c)  dissolved  air  ? 

10.  Give  the  formulas  of  a  compound  of  H  and  S  and 
of  two  oxides  of  sulphur.     Show  by  equations  how  each  of 
these  oxides  of  S  would  react  with  a  water  solution  of 
NaOH. 

11.  Give  the  volume  relations  between  the  gases  in  the 
following  reactions :   hydrogen  and  chlorine  combining  to 
form   hydrochloric  acid ;    hydrogen  and   oxygen    to    form 
steam ;    hydrogen  and    nitrogen    to  form  ammonia.     If  a 
million  molecules  of  H  took  part  in  each  reaction,  how 
many  molecules  of  each  product  would  be  formed  ? 

12.  If  to  36  g.  of  water  at  ordinary  temperature  we  add 
metallic  sodium  until  no  further  reaction  takes  place,  what 
weight  of  H  will  be  set  free  ?    What  volume  will  it  occupy 
at  18°  and  740  mm.  ?   What  proportions  of  the  H  originally 
contained  in  the  water  will  it  constitute  ?    What  weight 
of  Na  will   suffice  ?    How  many  gram-atoms  of  Na  will 
this  be  ?    How  many  gram-molecular  volumes  will  the  H 
occupy  ? 

13.  Show  how  the  composition  of  water  may  be  deter- 
mined by  weight  and   by  volume. 

14.  Distinguish  between  hard  and  soft  waters.   How  are 
lianl  \\airrs   sol'tcucd  '.'     I  low  do   we  obtain  pure   water? 


HYDROGEN  AND  WATER  21 

How  does  pure  water  at  ordinary  room  temperature  behave 
when  heated  to  100°  C.  or  cooled  to  0°  C.  ? 

15.  Describe  the  process  by  which  water  may  be  decom- 
posed by  electrolysis,  touching  on  apparatus  generally  used 
and  method  of  collecting  the  resulting  gases.    Name  the 
gases  and  give  the  test  for  each. 

16.  What  is  meant  by  a  solution  of  a  substance  ?  Describe 
an  experiment   illustrating    (a)   saturated  solution;    (b)  a 
supersaturated  solution. 

17.  Distinguish  in  composition  between  water  of  perma- 
nent hardness  and  that  of  temporary  hardness,  and  state 
how  each  may  be  softened. 

18.  Dumas  and  Stas  obtained  the  result  of  nineteen  deter- 
minations of  the  gravimetric  composition  of  water  to  be  an 
average  of  840.161  g.  of  0  formed  from  945.439  g.  of  water. 
Calculate  the  ratio  of  combination. 

19.  If  crystallized  calcium  sulphate  contains  about  18  per 
cent  of  water,  what  volume  of  steam  at  200°  C.  and  755  mm. 
is  given  off  by  heating  100  g.  of  the  solid  until  all  the  water 
of  crystallization  is  expelled  ? 

20.  Calculate  the  volume  of  1  g.   of  H  under  standard 
conditions. 

21.  Iron  and  tin  ores  usually  are  oxides.    In  obtaining 
the  metals  Avhat  kind  of  reactions  are  used  ? 

22.  What  changes  would  take  place  in  nature  if  water  did 
not  expand  (rr)  when  cooled  below  4°  C.  ?  (&)  when  it  freezes  ? 

23.  The  gas  density  of  water  vapor  is  about  9.    Calculate 
the  volume  occupied  by  1  g.  of  water  when  in  the  form  of 
si  cam  at  100°.  When  the  steam  is  doubled  in  volume,  to 
what  temperature  would  it   have  1o  l»e  heated? 

24.  How  could  you  determine  the  total  amount  of  solid 
material  contained  in  a  sample  of  water  ? 


22  REVIEW  QUESTIONS  AND  PROBLEMS 

25.  How  may  it  be  ascertained  by  experiment  that  water 
contains  the  elements  hydrogen  and  oxygen  and  these  two 
elements  only  ? 

26.  What  weight  of  H  will  be  required  for  the  complete 
reduction  of  10  g.  of  CuO  ?  At  740mm.  and  15°  C.  what 
will  be  the  volume  of  the  H  ? 

27.  What  is  meant  by  "  water  of  crystallization,"  and 
what  relation  does  it  bear  to  the  terms  "efflorescence"  and 
"  deliquescence  "  ? 

28.  Describe  three  methods  of  obtaining  hydrogen  by  the 
decomposition  of  water. 

29.  Describe  the  essential  features  of  the  "  mechanical 
nlethod  "  of  water  filtration. 

30.  How  may  impure  water  be  rendered  fit  for  drinking 
purposes  ? 

31.  How  would  you  prove  that  the  composition  of  water 
is  expressed  by  the  formula  H20  ? 

32.  A  liter  of  H  weighs  0.0899  g.    A  liter  of  oxygen 
weighs  1.429  g.   Explain  the  significance  of  the  term  "atomic 
weight,"  and  explain  the  calculation  of  the  atomic  weight 
of  0  from  the  above  data. 

33.  Describe  an  experiment  illustrating  the  solubility  of 
ammonia  in  water. 

34.  One  volume  of  oxygen  at  80°  C.  will  go  to  form  how 
many  volumes  of  steam  under  the  same  conditions  ?    How 
will  the  number  of  molecules  of  each  compare  ?   What  in- 
ference can  be  drawn  from  the  last  answer  as  to  the  char- 
acter of  the  0  molecule  ?    How  do  we  account   for   the 
increase  in  the  density  when  0  is  converted  into  ozone  ? 

35.  To  what  constituent  do  acids  owe  their  characteris- 
tic properties?    Does  this  substance  impart  these  proper- 
ties to  all  its  compounds  ?    What  is  the  theory  advanced 


HYDROGEN  AND  WATER  23 

to  explain  the  facts  embraced  in  your  answer  ?  How  do  we 
explain  the  fact  that  some  acids  are  stronger  than  others  ? 
Name  some  other  facts  which  the  above-mentioned  theory 
explains. 

36.  What  weight  of  Zn  would  be  required  for  the  pro- 
duction of  sufficient  H  at  21°  C.  and  745  mm.  pressure  to  fill 
a  balloon  with  a  capacity  of  100  cc.  ? 

37.  Make  a  sketch  of  an  apparatus  employed  for  the 
electrolysis  of  water;    explain  the  process  and  state  the 
significance  of  the  result. 

38.  State  all  that  takes  place  when  steam  is  passed  over 
heated  iron.    How  may  the  gaseous  product  of  the  reaction 
be  identified  ?  Make  a  sketch  of  the  apparatus  which  might 
be  used  to  carry  out  this  experiment.    Making  use  of  the 
solid  product,  outline  an  experiment  to  illustrate  the  pro- 
duction of  water. 

39.  How  much  sodium  by  its  action  upon  water  is  required 
to  furnish  76  1.  of  H  at  100°  C.  and  746  mm.  ? 

40.  How  may  it  be  shown  experimentally  that  ammonia 
consists  of  H  and  N  ? 

41.  What  are  hydrazine  and  hydrazoic  acid ?  Discuss  their 
properties. 

42.  32.3  cc.  of  H  at  18°  C.  and  744  mm.  are  introduced 
into  a  eudiometer,  56.8  cc.  of  ()  at  20°  C.  and  745  mm.  added. 
Which  gas  and  how  much  of  it  at  21°  C.  and  745  mm.  will  be 
left  after  the  explosion,  if  the  tension  of  the  aqueous  vapor 
produced  be  taken  into  account'.' 

43.  Show  how  the  composition  of  water  and  of  hydrogen 
peroxide  illustrate  the  Law  of  Multiple  Proportions. 

44.  Would  you  use  Zn  or  Fe  for  making  H  to  fill  a  large 
balloon?    Why?    Would  H  make;  a  good  illuminating  gas  ? 

45.  Ts  water  an  oxide?  an  anhvdride? 


24  REVIEW  QUESTIONS  AND  PROBLEMS 

46.  The  density  of  Cl  is  nearly  thirty-six  times  that  of  H. 
Compare  its  rate  of  diffusion  with  that  of  H. 

47.  If  the  density  of  ice  is  .92,  what  volume  will  a  liter 
of  water  at  4°  C.  occupy  when  frozen  ? 

48.  Give  three  reasons  for  considering  that  water  is  not 
an  elementary  substance.    Define  the  terms  "  element "  and 
"  compound." 

49.  How  many  grams  of  H  can  be  obtained  by  treat- 
ing 30  g.  of  Zn  with  sulphuric  acid,  and  what  will  be  the 
volume  at  20°  C.  and  760  mm.  ? 


CHAPTER  XI 
NITROGEN  GROUP  AND  AIR 

1.  How  can  ammonia  be  made  from  ammonium  chloride  ? 
Write  equations  to  show  how  ammonium  hydroxide  reacts 
with  nitric  acid  and  aluminum  chloride. 

2.  Calculate  the  volume  that  10 1.  of  air  at  25°  C.  would 
occupy  at  0°  C. 

3.  Give  the  name  and  formula  for  the  common  nitrogen 
:icid.    From  what  is  it  usually  made  and  how?    Illustrate 
the  important  chemical  properties  of  the  acid  by  equations 
for  its  reactions  with  both  zinc  and  zinc  oxide. 

4.  Explain  the  fact  that  when  strong  nitric  acid  acts  on 
copper,  red  fumes  are  evolved.    Illustrate  your  explanation 
by  equations. 

5.  Give  the  formulas  for  two  common  oxides  of  phos- 
phorus ;    also   for  two  common    oxides   of  arsenic.    Write 
the  equations  for  reactions  showing  the  formation  of  two 
salts  containing  phosphorus,  and  of  two  salts  containing 
arsenic. 


NITRO<;i:X   (JROUP  AND  AIR  25 

6.  Show  by  equations  the  different  effects  of  concen- 
trated nitric  acid  on  copper,  cuprous  oxide,  and  cupric  oxide. 

7.  How  do  arsenic  and  antimony  differ  from  the  true 
metals  ? 

8.  Give  the  reaction  equations  for  the  preparation  of 
the  following  substances  :  ammonia,  nitric  acid,  nitric  oxide, 
nitrous  oxide,  phosphorus. 

9.  What  volume  of  ammonia  gas,  at  a  temperature  of 
20°  C.  and  a  pressure  of  740  mm.  of  mercury,  can  be  obtained 
from  214  g.  of  sal  ammoniac,  and  how  should  one  proceed 
to  prepare  it  ? 

10.  Name  and   describe   the   elements   of  the  nitrogen 
family ;  mention  the  group  to  which  they  belong  and  state 
its  general  characteristics. 

11.  Give  the  sources,  preparation,  properties,  and  uses  of 
nitric  acid. 

12.  Write  the  formulas  of  the  potassium  and  ammonium 
salts  of  sulphuric  and  nitric  acids ;  of  nitrogen  peroxide. 

13.  Why  is  it  impossible  to  write  a  chemical  formula 
of  air  ?    Why  is  a  mixture  of  air  with  illuminating  gas 
explosive  ? 

14.  Write  the  equations  for  («)  the  neutralization  of  potas- 
sium hydroxide  and  nitric  acid;  (A)  preparation  of  nitrogen 
from  sodium  nitrite  and  ammonium  chloride. 

15.  Give,   with   equation,  a  jnethod    of    preparation  of 
ammonia  and  state  the  properties  of  the  substance. 

16.  Write   the    formula    for   primary   ammonium    phos- 
phate, secondary  potassium  phosphate,  ammonium  sulphate, 
calcium  phosphate,  sodium  nitrate. 

17.  Write  the  names  and  formulas  of  the  live  oxides  of 
nitrogen.     Give  a  brief  statement  of   the   important    law 
illustrated  by  these  compounds. 


26  REVIEW  QUESTIONS  AND  PROBLEMS 

18.  What  are  the  constituents  of  the  atmosphere :  («)  per- 
manent ?   (b)  variable  ? 

19.  What  weight  of  nitrous  oxide  will  be  formed  when 
80  g.  of  ammonium  nitrate  is  decomposed  by  heat  ?    What 
will  be  the  volume  of  this  nitrous  oxide  at  745  mm.  pressure 
and  a  temperature  of  18°  C.  ? 

20.  Give  the  structural   formulas  of  NH4CL,  NH4OH, 
and  (NH4)2S04. 

21.  The  formula  of  phosphoric  acid  is  HgPO4.    What  is 
the  formula  of  primary  sodium  phosphate  ?  secondary  am- 
monium phosphate  ?  normal  calcium  phosphate  ?  secondary 
calcium  phosphate  ? 

22.  The  specific  gravity  of  ammonia  compared  to  H  is 
8.5.   What  is  its  molecular  weight?    Explain  the  steps  by 
which  this  result  is  reached. 

23.  Discuss   the  preparation   of   P  as  to  equation   and 
method  and  describe  its  allotropic  forms. 

24.  How  is  ammonia  used  in  refrigeration  ?  Describe  the 
methods  of  preparation  and  the  properties  of  liquid  air. 

25.  From  what  material  and  by  what  process  may  white 
phosphorus  be  made  ?  What  are  its  properties  and  for  what 
is  it  used  ?    How  may  it  be  converted  into  red  phosphorus  ? 

26.  What  is  white  arsenic  ?    How  may  arsenic  be  detected 
in  a  case  of  suspected  poisoning  ? 

27.  Give  two  reasons  for  the  belief  that  the  nitrogen 
and  the   oxygen  in  the  atmosphere   are   mixed   and    not 
combined. 

28.  In  what  great  industry  is  calcium  phosphate  (normal) 
employed?    To  what  treatment  must  it  he  subjected?  How 
may  free  phosphorus  be  prepared  ?  What  is  its  usual  source? 

29.  Give  the  sources,  method  of  preparation,  and  proper- 
ties of  the  element  nitrogen. 


NITROGEN  GROUP  AND  AIR  27 

30.  Give  the  equation  for  the  reaction  that  takes  place 
when   laughing   gas  is    prepared.     Make  a  sketch  of   the 
apparatus  used. 

31.  Give   formulas  and   names  of   some  compounds  of 
phosphorus,  arsenic,  and  nitrogen,  which  are  analogous  in 
their  formulas  and  chemical  behavior. 

32.  Which  of   the  constituents  of   the   atmosphere  are 
essential  to  animal  life  and  which  to  plant  life  ?  •  What  is 
returned  to  the  atmosphere  by  animals  and  what  by  plants  ? 
Give  two  reasons  to  show  that  these  constituents  of  the 
atmosphere  are  not  in  chemical  combination. 

33.  What  is  the  commercial  source  of  ammonia?    How  is 
it  prepared  (equation)  and  how  may  it  be  shown  (a)  that  it 
has  the  character  of  a  base,  (/>)  is  lighter  than  air,  (c)  and 
is  readily  soluble  in  water  ? 

34.  When  N  is  prepared  from  the  atmosphere  what  other 
element  does  the  gas  contain  ?    Name  two  different  ways  in 
which  the  salts  of  nitric  acid  may  be  prepared. 

35.  Compare  the  properties  of  the  two  common  modifica- 
tions of  phosphorus.    What  is  the  formula  of  the  product 
of  the  combination  of  phosphorus  in  oxygen,  and  what  name 
is  given   to   this  compound  which    indicates   its  chemical 
behavior  ? 

36.  Name  two  metals  which  are  not  readily  acted  upon 
by  the  atmosphere.    For  what  purposes  does  this  property 
of  these  metals  render  them  particularly  serviceable  ? 

37.  Name  the  compounds  commonly  used  as  the  sources 
of    nitrogen,    phosphorus,    and    potassium    in    commercial 
fertilizer.    How  is  the  nitrogen  of  the  air  made  available 
f<>r  plant  food? 

38.  How  could  you  show  the  presence  of  four  substances 
in  the  air  ? 


28  REVIEW  QUESTIONS  AND  PROBLEMS 

39.  Write  the  graphic  formula  of  arsenic  trioxide.    De- 
scribe its  preparation  and  mention  its  important  properties 
and  uses. 

40.  Describe  a  method  of  preparing  hydrogen  arsenide. 
Give  equation.    State  the  ordinary  use  of  hydrogen  arsenide. 

41.  Explain  the  instability  of  nitrogen  compounds.    De- 
scribe an  experiment  illustrating  this  instability. 

42.  Describe  a  process  of  extracting  the  metal  arsenic 
from  one  of  its  ores.    Mention  the  physical  and  chemical 
properties  of  arsenic. 

43.  Describe  in  detail  Marsh's  test  for  arsenic  and  write 
the  reaction. 

44.  Two   compounds    have   the    following   composition : 
(«)  phosphorus    56.36   per   cent,   oxygen    43.64    per  cent; 
(&)  phosphorus  43.65  per  cent,  oxygen  56.35  per  cent.    Show 
whether  or  not  the  Law  of  Multiple  Proportion  holds. 

45.  Give  the  name  and  compound  formed  («)  when  phos- 
phorus burns  in  air ;  (7/)  when  the  product  is  treated  with 
water  and  the  solution  boiled.    Write  the  equations  for  both 
reactions. 

46.  Mention    four    gaseous    components    of    the    atmos- 
phere and  tell  briefly  how  you  .would  demonstrate  their 
presence. 

47.  Describe  the  preparation  of  ammonium  chloride  as  a 
by-product  in  the  manufacture  of  illuminating  gas  from 
coal.    Give  the  important  uses  of  ammonium  chloride. 

48.  Give  the  composition  of  ordinary  gunpowder.   Explain 
the  expansive  force  of  ignited  gunpowder  and  write  the 
reaction  that  takes  place. 

49.  Give  at  least  two  reasons   for  the    belief  that  the 
oxygen  and  nitrogen  of  the  atmosphere  are  not  in  chemical 
combination. 


OXYGEN-SULPHUR  GROUP  29 

50.  What  chemical  changes  are  produced  by  the  action  of 
lightning  in  the  air  ?   Does  atmospheric  N  differ  from  that 
obtained  from  a  compound  ? 

51.  Name  the  members  of  the  nitrogen  family,  tabulate 
their  resemblances  and  analogous  compounds,  and  show  how 
that  relation  illustrates  the  basis  of  the  natural  classification 
of  the  elements. 

52.  When  ammonia  and  air  are  heated  and  passed  over 
the  catalytic  agent  (spongy  platinum)  nitric  acid  is  formed. 
What  does  this  prove  as  to  the  composition  of  nitric  acid  ? 

53.  What  happens  to  nitric  acid  when  passed  through  a 
red-hot  tube  ?  What  is  the  effect  of  heat  upon  («)  potassium 
nitrate  ?  (f>)  lead  nitrate  ?  (c)  ammonium  nitrate  ? 


CHAPTER  XII 
OXYGEN-SULPHUR  GROUP 

1.  What  volume  of  oxygen,  measured  under  standard 
conditions,  will  be  evolved  when  198  g.  of  mercuric  oxide 
are  decomposed  by  heating?    What  will  be  the  volume  of 
the  oxygen  at  770  mm.  pressure  and  27°  C.  ? 

2.  When  2  g.  of  a  certain  substance  were  heated,  all 
the  oxygen  which  the  substance  contained  was  given  off 
and  the  residue  weighing  1.97  g.  was  left.    Calculate  the 
percentage  of  oxygen  in  the  substance. 

3.  Describe  briefly  experiments  in  the  laboratory  to  illus- 
trate the  effect  of  heat  on  sulphur  (the  air  excluded). 

4.  State  briefly  how  you  could  distinguish  between 

1.  Concentrated  and  dilute  sulphuric  acid. 

2.  Sodium  chloride  and  sodium  sulphate. 

3.  Copper  sulphate  and  potassium  sulphate. 


30  REVIEW  QUESTIONS  AND  PROBLEMS    - 

5.  State  what  substances   you  would  use  to  prepare : 
(a)  S02;  (6)H2S;  (c)  CO ;  (rf)  CO2. 

6.  Describe  how  you  would  prepare  S02  in  the  laboratory. 
Give  its  physical  and  chemical  properties.    How  may  it  be 
converted  into  H2S04  ?   How  could  you  distinguish  a  solu- 
tion of  sulphurous  acid  from  sulphuric  acid  ? 

7.  Name  some  of  the  chemical  results  which  might  be 
expected  if  the  atmosphere  were  composed  entirely  of  0. 

8.  How  is  hydrogen  sulphide  made  ?    Mention  the  im- 
portant physical  properties  ;  the  chemical. 

9.  What  is  formed  when  a  solution  of  sodium  hydroxide 
is  saturated  with  hydrogen  sulphide  ? 

10.  What  is  the  principal  product  when  sulphur  burns  in 
the  air  ?    Give  two  physical  properties  of  the  compound 
and  show  by  equations  how  it  reacts  with  water  and  with 
two  different  oxidizing  solutions. 

11.  Write  the  equations  showing  the  reactions  of  dilute 
sulphuric  acid  with  the  following  substances :  (a)  sodium 
sulphide ;  (6)  potassium  carbonate ;  (c)  ammonium  hydroxide ; 
(d)  cupric  oxide ;  (e)  aluminum  hydroxide  ;  (/)  lead  nitrate ; 
(ff)  barium  chloride ;  (A)  zinc. 

12.  Give  the  formulas  for  the  common  oxides  of  phos- 
phorus, calcium,  copper,  and  silicon.    Which  of  these  oxides 
unite  readily  with  water  ?    Give  the  names  and  the  formulas 

*for  the  compounds  so  formed. 

13.  Calculate  the  volume  of  carbon  dioxide  at  20°  C.  and 
750  mm.  pressure  that  would  be  produced  by  burning  200  g. 
in  oxygen. 

14.  Write  the  formulas,  and  indicate  whether  basic  or 
acidic,  of  the  oxides  of  the  following  elements :  aluminum, 
barium,  iron,  phosphorus,  silicon,  sodium,  sulphur. 


OXYGEN-SULPHUR  GROUP  31 

15.  Show  that  the  preparation  of  sulphur  dioxide  from  a 
sulphite  is  similar  in  principle  to  the  preparation  of  hydrogen 
sulphide. 

16.  Calculate   the   percentage    composition    of    sulphur- 
ous anhydride  and  sulphuric  anhydride.    Show  how  these 
two  substances  are  in  harmony  with  the  Law  of  Multiple 
Proportions. 

17.  How  many  pounds  of  sulphur  would  be  necessary  in 
the  preparation  of  100  Ib.  of  90  per  cent  sulphuric  acid  ? 

18.  Write  the  names  and  formulas  of  the  oxides  and 
oxygen  acids  of  selenium  and  tellurium. 

19.  What  weight  of  potassium  chlorate  is  necessary  to 
prepare  200  1.  of  oxygen  at  20°  C.  and  750  mm.,  and  what  is 
its  productive  cost  at  .50  ct.  per  kilogram  ? 

20.  How  does  a  mixture  of  potassium  chlorate  and  man- 
ganese dioxide  act  when  heated  ?    What  gas  is  evolved  ? 
Is  there  interaction,  and  if  not,  what  is  such  a  process  called  ? 

21.  Distinguish  between  combustion,  decay,  oxidation, 
and  putrefaction. 

22.  Explain  spontaneous  combustion  and  give  examples. 

23.  Compare  the  manufacture  of  sulphur  with  that  of 
charcoal. 

24.  Coal  often  contains  iron  pyrites.    What  sulphur  com- 
pounds do  you  think  would  be  found  in  illuminating  gas 
made  from  such  coal  ? 

25.  How  would  you  distinguish  between  a  sulphide,  a  sul- 
phite, and  a  sulphate  ? 

26.  How  much,  both  by  weight   and  by  volume,  is  re- 
quired to  burn  100  g.  of  S  containing  12  per  cent  of  incom- 
bustible impurities  ? 

27.  Describe  the  occurrence  of  sulphur  in  nature  and  state 
the  uses  to  which  it  is  put. 


32  REVIEW  QUESTIONS  AND  PROBLEMS 

28.  State  three  ways  of  preparing  S02  and  tell  how  it  is 
converted  into  SOg. 

29.  With  the  aid  of  Avogadro's  hypothesis  calculate  the 
volume  of  oxygen  that  will  be  required  for  the  complete 
combustion  of  10 1.  of  the  following  gases :  (a)  acetylene ; 
(&)  methane ;  (c)  ethane,  C2H6 ;  (d)  ethylene,  C2H4 ;  (e)  CO. 
What  volume  of  C02  will  be  formed  in  each  case  ? 

30.  How  does   ozone   differ  from   oxygen  ?    How  may 
ozone  be  prepared  ?    What  are  its  properties  and  uses  ? 
Give  in  full  the  properties  of  oxygen. 

31.  Give  the  properties  of  H2S04  and  describe  its  prep- 
aration by  the  "  contact "  process. 

32.  Give  three  methods  for  the  preparation  of  oxygen  and 
explain  what  relation  it  bears  to  respiration  and  combustion. 

33.  How  much  H2S04  and  zinc  would  be  needed  to  fill 
1100  balloons,  each  of  a  capacity  of  2000  cc.,  with  hydrogen 
at  a  pressure  of  1000  mm.  of  mercury  ? 

34.  Describe  (with  sketches)  two  experiments  by  means 
of  which  it  may  be  shown  that  under  certain  conditions  a 
gas  ordinarily  spoken  of  as  a  supporter  of  combustion  may 
become  a  combustible. 

35.  Define  oxidation  and  reduction  and  give  two  examples 
of  each.    Describe  three  experiments  to  illustrate  the  differ- 
ence between  the  properties  of  oxygen  and  atmospheric  air. 

36.  The  weight  of  a  liter  of  O  under  standard  conditions 
is  1.429  g.    What  volume  will  25  kg.  of  0  occupy  at  a  tem- 
perature of  18°  C.  and  a  pressure  of  740  mm.  ? 

37.  What  volume  of  a  solution  of  H2S04  containing  196  g. 
of  the  acid  per  liter  will  be  required  for  the  exact  neutral- 
ization of  100  cc.  of  a  solution  of  NaOH  containing  40  g.  to 
the  liter  ? 

38.  Give  all  possible  uses  of  H2SO4. 


OXYGEN-SULPHUR  GROUP  33 

39.  Write  equations  showing  the  result  of  adding  H2S04 
to  (a)  iron  ;  (7>)  quicklime ;  (c)  a  solution  of  barium  chloride. 
What   is   the   chemical    change   which   takes  place  when 
HaS04  is  added  to  sugar? 

40.  Under   what   conditions   is    native   sulphur  usually 
found  ?    Name  two  classes  of  sulphur  compounds  which 
occur  in  nature. 

41.  How  may  S02  be  prepared  by  (a)  an  oxidizing  proc- 
ess ?  (&)  by  reduction  ? 

42.  How  many  grams  of  copper  sulphide  can  be  formed 
by  burning  2  g.  of  copper  in  sulphur  vapor  ? 

43.  Explain   the  chemical    difference    in   the   bleaching 
action  of  SO2  and  Cl. 

44.  Describe  («)  the  principal  sources  of  sulphur  in  nature. 
(l>)  State  one  method  of  preparation,  (c)  Mention  allotropic 
forms. 

45.  Explain  why  the  gaseous  product  produced  by  the 
action  of  H2SO4  with  copper  differs  from  that  usually  pro- 
duced by  the  action  of  an  acid  with  a  metal. 

46.  Give  the  proportions  of  0  in  normal  air  by  weight 
and  by  volume   and  describe  a  laboratory  experiment  to 
show  how  each  of  these  proportions  are  determined. 

47.  Describe  an  experiment  showing  the  value  of  H2S  as 
a  reducing  agent.    State  the  property  of  H2S  to  which  its 
value  as  a  reducing  agent  is  due. 

48.  Berzelius  converted  10.000  g.  of  lead  into  14.642  g. 
of  lead  sulphate  (PbSO4).   The  atomic  weights  of  lead  and  of 
oxygen  are  206.91  and  16.00.    Calculate  the  atomic  weights 
of  sulphur. 

49.  Is  the  equation  for  the  preparation  of  hydrosulphuric 
acid  a  reversible  one  ?  As  ordinarily  carried  out,  does  it  com- 
plete itself  ?  Does  dry  hydrosulphuric  acid  react  with  litmus  ? 


34  REVIEW  QUESTIONS  AND  PROBLEMS 

60.  In  what  respects  is  sulphurous  acid  like  carbonic  acid  ? 

51.  How  does   a   mixture  of   chlorate   and    manganese 
dioxide   act   when  heated  ?    Calculate   the    volume   under 
standard  conditions  and  also  the  weight  of  the  gas  pro- 
duced if  245  g.  of  chlorate  are  used. 

52.  Describe  a  method  of  preparing  oxygen,  describe  its 
properties,  and  relate  the  history  of  its  discovery. 

53.  Describe  the  lead-chamber  process  for  the  manufacture 
of  H2S04. 

54.  Define  combustion  and  kindling  temperature.   Give  an 
account  of  the  discovery  of  oxygen  and  of  the  effect  which 
the  study  of  its  properties  had  upon  the  development  of  the 
science  of  chemistry. 

CHAPTER  XIII 
CARBON,  SILICON,  TIN,  LEAD  GROUP 

1.  Compare  the  composition,  manner  of  formation,  and 
properties  of  the  oxides  of  carbon,  silicon,  tin,  and  lead. 

2.  How  do  you  account  for  a  weak  acid  such  as  H2C03 
being  able  to  decompose  such  stable  compounds  as  the  sili- 
cates, as  illustrated  by  the  weathering  of  rocks  ? 

3.  A  certain  ore  has  90  per  cent  galena.    How  much 
pure  lead  can  be  obtained  from  a  ton  of  the  ore  ? 

4.  If  white  lead  were  mixed  with  barium  sulphate,  how 
could  you  detect  the  adulteration  ? 

5.  What  are  hydrocarbons  and  where  are  they  found  ? 
Mention  three  hydrocarbons  present  in  illuminating  gas. 

6.  Why  does  the  air  of  a  tightly  closed  room  in  which 
lamps  are  burning  become  unfit  to  breathe  ?    What  is  the 
explanation  of  the  explosions  which  often  occur  in  houses 
when  illuminating  gas  has  been  escaping  ? 


CARBON,  SILICON,  TIN,  LEAD  GROUP  35 

7.  What  is  the  purpose  in  using  baking  soda  in  dough  ? 
Why  does  a  lamp  burn  better  with  the  chimney  on  than  off  ? 

8.  Describe  the  manufacture  of  white  lead,  giving  equa- 
tions and  uses. 

9.  Discuss  combustion,  the  nature  of  a  flame,  and  the 
factors  which  cause  and  modify  the  luminosity  of  a  flame. 

10.  Describe  fully  the  oxides  of  carbon  and  the  ways 
in  which  they  are  formed  and  prepared. 

11.  Point  out  the  chemical  similarity  between  carbon  and 
silicon. 

12.  Give  (a)  the  equation  for  the  combustion  of  carbon 
monoxide  in  oxygen,    (i)  What  will  be  the  relative  volumes 
of  the  gases  taking  part  in  the  reaction  ?  (c)  What  will  be  the 
relative  weights  of  the  gases  ?  (d)  If  56  g.  of  carbon  monoxide 
are  used,  what  will  be  the  volumes  of  oxygen  required  under 
standard  conditions  ? 

13.  Calculate  the  volume  occupied  by  10  g.   of  carbon 
dioxide  at  27°  C.  and  38  cm.  pressure,  assuming  that  1  g.  of 
C02  at  0°  C.  and  76  cm.  occupies  .509  1. 

14.  Calculate  the  weight  of  sodium  hydroxide  that  would 
react  with  22.4 1.  of  C02  under  normal  conditions  of  tem- 
perature and  pressure,  sodium  hydroxide  to  be  in  excess. 

15.  State  from  personal  experience  how  C02  was  pre- 
pared in  the  laboratory,  and  write  the  reaction  involved. 
State  two  properties  of   CO2  which  were  ascertained   by 
experiment.    How  may  it  be  shown  that  C02  is  one  of  the 
products  of  respiration  ? 

16.  What  do  you  consider  the  most  important  compound 
of  (a)  carbon  ?  (ft)  silicon  ?  (c)  tin  ?  (d)  lead  ?    Why  ? 

17.  How  does  the  total  weight  of  the  products  of  com- 
bustion of  a  candle  compare  with  the  total  weight  of  the 
materials  taking  part  in  the  combustion  ?   Name  and  state 
the  law  which  this  illustrates. 


36  REVIEW  QUESTIONS  AND  PROBLEMS 

18.  State  a  chemical  method  of  distinguishing  between 
CO  and  C02  and  describe  a  method  by  which  each  may  be 
converted  into  the  other. 

19.  Name  an  important  ore  of  lead.    How  would  you 
proceed  to  get  metallic  lead  into  solution  ?   Give  the  formula 
of  the  resulting  compounds  of  lead. 

20.  Name  two  natural  and  two  artificial  modifications  of 
the  element  carbon.    What  are  the  chief  products  resulting 
from  the  heating  of  soft  coal  without  access  of  air  ?    How 
does  coal  gas  differ  chemically  from  water  gas  ?   Under  what 
conditions  does  a  combustible  substance  burn  with  a  flame  ? 
Name  two  purposes  for  which  graphite  is  commonly  used. 

21.  Name  the  substances  used   in   the  manufacture  of 
glass.    How  does  the  composition  of  hard  glass  differ  from 
that  of  soft  glass  ? 

22.  How  is  water  gas  made  ?   What  gases  does  it  contain  ? 
Why  is  it  carburetted  (enriched)  ?    To  what  constituent  is 
the  poisonous  character  chiefly  due  ? 

23.  Give  the  chemical  name  and  the  mineralogical  name 
of  one  important  ore  of  lead.    Describe  briefly  the  mode  of 
extracting  the  metal,  name  two  practical  uses  to  which  it  is 
put,  and  state  what  property  renders  it  particularly  suited 
to  each  purpose  named.    What  metals  are  components  of 
solder  and  brass  ? 

24.  Discuss  the  chemical  changes  which  take  place  in  a 
furnace  fire,  as  follows  : 

1.  What  substances  cause  the  blue  flame  at  the  surface 

of  the  coal  and  how  is  it  formed  ? 

2.  State  and  give  reasons  for  the  effects  of  admitting 

air  (a)  to  the  top  of  the  fire ;  (b)  to  the  bottom. 

3.  How  does  anthracite  coal  differ  from  bituminous 

in  appearance  and  chemical  quality  ? 


CARBON,  SILICON,  TIN,  LEAD  GROUP  37 

25.  Draw  a  vertical  section  (diagram  of  a  candle  flame), 
showing  its  structure.    Indicate  on  the  diagram  the  part  of 
the  flame  having  (a)  greatest  luminosity ;  (6)  greatest  heat. 

26.  Find  the  weight  of  each  of  the  products  of  combustion 
when  78  g.  of  acetylene  are  burned. 

27.  Write  in  order  the  chemical  name  and  the  formula 
of  each  of  five  members  of  the  marsh-gas  series. 

28.  Describe    the    process    of    fractional    distillation   of 
petroleum.    Mention  three  useful  products  derived  from  it, 
with  formulas. 

29.  Distinguish  as  to  chemical  composition  and  properties 
between  fire  damp  and  choke  damp  and  explain  why  each 
is  dangerous  in  mines. 

30.  Describe  in  detail  a  process  of  manufacturing  lead 
carbonate  on  a  commercial  scale.    State  the  principal  use 
of  it. 

31.  Give  the  construction  of  the  Davy  safety  lamp  and 
describe  a  laboratory  experiment  to  illustrate  the  principle 
on  which  its  safety  depends. 

32.  Describe  the  construction  and  explain  the  operation 
of  a  Bunsen  burner. 

33.  Compare  the  action  of  carbon  and  chlorine  as  disin- 
fecting agents. 

34.  Give   the  theory  to   account   for   the  formation   of 
(«)  petroleum ;  (6)  natural  gas. 

35.  Describe  a  method  of  preparing  acetylene  and  state 
its  physical  and  chemical  properties. 

36.  (")  Explain  the  formation  of  marsh  gas  in  nature. 
(6)  Distinguish    between    carbohydrate    and    hydrocarbon, 
(c)  Mention  two  groups  of  carbohydrates. 

37.  Describe  the  manufacture  of  glass  and  distinguish 
between  window  glass  and  green  bottle  glass. 


38  REVIEW  QUESTIONS  AND  PROBLEMS 

38.  Mention  («)  the  principal  products  obtained  from  the 
destructive  distillation  of  bituminous  coal ;  (b)  two  great 
natural  sources  of  C02.    (c)  Explain  why  the  percentage  of 
C02  in  the  air  remains  nearly  uniform. 

39.  Describe  the  preparation  and  give  the  properties  and 
uses  of  (a)  lampblack ;  (6)  coke,    (c)  What  is  the  source  of 
gas  carbon  and  its  use  ? 

40.  If  a  candle  consists  of  87  per  cent  carbon  and  of 
13  per  cent  hydrogen,  what  weights  of  C02  and  of  H20  will 
be  formed  when  50  g.  of  the  candle  burn  ? 

41.  What  weight  of  CO  will  be  formed  upon  treating 
25  g.  of  oxalic  acid  with  concentrated  sulphuric  acid  ? 

42.  Name  the  natural  and  artificial  forms  of  free  carbon 
and  state  how  they  differ  from  one  another. 

43.  What  volume  of  C02  would  be  formed  respectively 
by  the  complete  combustion  of  (ft)  12  1.  of  acetylene  ?  (i)  7  1. 
of  propane  (CJIJ  ?  (c)  75  cc.  of  CO?  (d)  2.5 1.  of  methane? 
(e)  4 1.  of  ethylene  (C2H4)  ? 

44.  Through  what  cycle  does  carbon  pass  in  animal  and 
vegetable  life  ? 

45.  How  may  coke  be  converted  into  graphite  ?    What  is 
animal  charcoal  ?    For  what  purpose  is  it  used  ? 

46.  Describe  («)  the  process  employed  in  the  manufacture 
of  carborundum.    Of  what  practical  use  is  the  substance  ? 
(i)  In  what  forms  does  silica  occur  in  nature  ?    In  what 
industry  are  silica  and  the  silicates  of  great  importance  ? 

47.  Calculate  the  weight  of  calcium  carbonate  that  could 
be  precipitated  by  the  action  of  10  1.  of  C02  (measured  under 
745  mm.  pressure  at  21°  C.)  upon  a  solution  of  Ca(OH)2. 

48.  Name  three  allotropic  forms  of  carbon  and  show  how 
their  chemical  identity  may  be  proved.    By  what  reaction 
may  C02  be  distinguished  from  CO  ? 


CARBON,  SILICON,  TIN,  LEAD  GROUP  39 

49.  What   is    allotropy   and    how  is    it  illustrated    and 
accounted  for  in  the  case  of  the  element  carton  ? 

50.  Name  three  important  substances  obtained   by  the 
destructive  distillation  of  (W)  wood ;  (/>)  soft  coal. 

51.  What  is  an  alloy?    Mention  an  alloy  and  state  three 
ways  in  which  its  properties  differ  from  those  of  its  constit- 
uents.   Name  an  alloy  of  lead  and  of  tin. 

52.  Make  a  comparison  between  («)  carbon  and  silicon  as 
to  compounds  formed ;  (/»)  between  carbon,  oxygen,  sulphur, 
and  phosphorus  as  to  allotropic  forms. 

53.  Suggest  a  probable  way  that  natural  gas  has  been 
formed. 

34.  Coal  frequently  contains  sulphide  of  iron.  What 
sulphur  compounds  are  likely  to  be  formed  when  gas  is 
made  from  such  coal,  and  what  would  be  the  method  for 
the  removal  of  these  compounds  ? 

55.  Could  a  solution  of  NaOH   be  substituted  for  the 
solution  of  Ca(OH)2  in  testing  for  CO2? 

56.  How  would  you  distinguish  between  C02,  and  O,  H, 
N,  and  NaO  ? 

57.  How  would  you  distinguish  between  carbonates  and 
sulphites  ? 

58.  Write  the  equations  for  the  preparation  of  MgCO8, 
BaCO8,  KaC08,  Na2CO8,  and  CaC08. 

59.  How  would  you  detect  the  presence  of  lead  in  tinfoil? 

60.  Since  stannous  chloride  reduces  gold  chloride,  give 
the  equation  for  extracting  gold. 

61.  What  sulphates  other  than  lead  are  insoluble  ? 

62.  (o.)  In  what  respect  is  silica  similar  to  tin  and  lead  ? 
(b)  Given  one  ton  of  cassiterite,  how  much  tin  could  be 
obtained  by  its  reduction  ? 


40  REVIEW  QUESTIONS  AND  PROBLEMS 

63.  How  can  you  determine  whether  a  given  crystal  is 
quartz  or  calc-spar  ? 

64.  Dumas,  in  1859,  added  to  a  solution  containing  4.5049 
of  stannous  chloride  an  excess  of  a  solution  of  silver  nitrate 
and  found  that  the  precipitate  of  silver  chloride  formed  con- 
tained 7.481  g.  of  silver.    What  is  the  atomic  weight  of  tin, 
if  the  atomic  weights  of  Cl  and  Ag  are  35.43  and  107.94 
respectively  ? 

65.  Explain   the   principle   of   the  chemical   fire   extin- 
guisher,   state    what    materials    are    used,    and    give    the 
equation. 

66.  Give  the  most  important  use  of  silicon  dioxide  and 
explain  why  silicon  is  not  found  free  in  nature. 

67.  What  is  water  glass  ?    How  is  it  produced  and  what 
are  its  uses  ? 

68.  Calculate  the  percentage  of  C02  and  CO  and  restate 
the  percentages  in  a  form  which  illustrates  the  Law  of 
Multiple  Proportions. 

69.  A  gaseous  hydrocarbon  contains  85.71  per  cent  of 
carbon ;  its  density  referred  to  oxygen  is  .875.    What  is  its 
simplest  formula  and  its  molecular  formula  ? 

70.  Write  the  formulas   for  the  following  compounds  : 
silicon   iodide,   hydrogen   silicide,  silicon  sulphide,  carbon 
silicide. 

71.  Write  the  equations  for  the  preparation  of  silicic  acid  ; 
carbonic  acid.    Write  the  formulas  of  the  following:  k-ud 
sodium  acetate,  stannous  bromide,  thorium  nitrate,  cerium 
sulphate,  lead  chromate,  lead  sulphide,  lead  tetroxide,  stannic 
chloride,  stannous  sulphide,  stannic  oxide. 

72.  Thorium  is  much  like  what  other  newly  discovered 
element  ? 

73.  How  is  animal  charcoal  obtained? 


THE  HALOGENS  41 

74.  Describe  the  manufacture  of  shot,  touching  on  (a)  sub- 
stances  used;    (6)  processes   used.    Explain   each   process 
mentioned.  Why  is  arsenic  used  in  the  manufacture  of  shot? 

75.  Give  a  laboratory  method  of  preparing  each  of  the 
oxides  of  carbon.   Compare  the  chemical  properties  of  these 
oxides  and  state  the  effects  of  each  on  animal  life.    Explain 
the  formation  of  each  in  a  coal  fire. 


CHAPTER  XIV 
THE  HALOGENS 

1.  How  may  chlorine,  bromine,  and  iodine  be  prepared  ? 
Write  the  equation  representing  the  reaction  involved  in 
each  case.    Why  are  these  elements  grouped  together? 

2.  Describe  another  method  for  the  preparation  of  chlo- 
rine and  write  the  equation  for  the  reaction  involved. 

3.  Why  is  moisture  necessary  to  the  bleaching  action  of 
Cl?    What  is  formed  when  hydrogen  burns  in  chlorine  and 
how  may  the  product  be  distinguished  from  chlorine  ? 

4.  («)  How  may  chlorine  be  prepared  ?    State  its  prop- 
erties.   (£»)  What  elements  constitute  the  halogen  group  and 
why  are  they  grouped  together  ? 

5.  Give  the  properties  of  Cl  and  state  what  is  formed 
when   it   is   passed   into   a    hot   concentrated   solution   of 
potassium  hydroxide. 

6.  What  weight  of  chlorine  will  be  set  free  when  a  so- 
lution containing  75  g.  of  sodium  chloride  is  electrolyzed, 
and  what  will  be  the  volume  of  the  chlorine  gas  thus  made 
at  a  temperature  of  20° C.  and  a  pressure  of  740  mm.? 

7.  How  many  liters  of  chlorine  can  be  obtained  from 
.  of  common  salt? 


42  REVIEW  QUESTIONS  AND  PROBLEMS 

8.  Name  the  principal  characteristics  of  each  of   the 
halogens  in  the  free  state.   Why  are  they  grouped  together  ? 
Describe  a  method  for  the  laboratory  preparation  of  free 
bromine  and  write  the  reaction. 

9.  What  is  the  chief  source  of  iodine  in  commerce  ? 
What  are  its  properties  ?  How  may  its  presence  be  detected  ? 

10.  Calculate  the  approximate  weights  in  grams  of  1 1. 
of  each  of  the  following  gases  :  C12,  HC1,  HBr,  HF. 

11.  What  weight  of  chlorine  can  be  prepared  from  78  g. 
of  rock  salt  containing  99  per  cent  NaCl  ?    How  much 
manganese  dioxide  and  sulphuric  acid  would  be  required  to 
carry  out  the  reaction  ?    What  volume  would  the  chlorine 
occupy  under  standard  conditions  ?    What  volume  of  hy- 
drochloric acid  would  be  formed  ? 

12.  Write  the  equation  for  preparing  hydrofluoric  acid. 
Describe  and  explain  the  process  of  etching  glass.   State  two 
methods  of  identifying  iodine. 

13.  Describe  and  explain  the  action  which  occurs  when 
chlorine  water  is  added  to  a  solution  of  potassium  iodide 
containing  starch. 

14.  If  100  g.  of  magnesium  are  completely  dissolved  in 
hydrochloric  acid,  what  volume  will  be  occupied  at  18°C. 
and  760  mm.  by  the  gas  evolved  ?    If  this  gas  is  then  burned 
in  oxygen,  what  substance  will  lie  produced  and  how  much  ? 

15.  If  a  quantity  of  a  gas  measures  493  1.  at  784  mm.  and 
20°  C.,  what  will  be  its  volume  under  standard  conditions  ? 
Supposing  the  gas  to  be  hydrogen  chloride,  calculate  its 
weight.    What  weights  of  materials  would  be  required  to 
prepare  it  ? 

16.  What  occurs  when  Cl  is  passed  into  («)  a  cold  and 
dilute  solution  of  potassium  hydroxide,  and  (ft)  into  a  hot 
and  concentrated  solution  ? 


THE  HALOGENS  43 

17.  Mention  some  important  chlorides  formed  in  nature ; 
some  that  are  artificially  produced. 

18.  Describe  in  detail  the  process  of  bleaching,  giving 
the  reaction  involved. 

19.  What   is   chlorinization  ?     What   are   the   tests    for 
chlorine  and  the  chlorides  ? 

20.  Give  the  reaction  involved  in  the  process  of  disin- 
fecting with  Cl. 

21.  Name  the  acids  of  Cl  and  write  and  name  the  zinc 
salt  of  each. 

22.  Compare  the  elements  of  the  halogen  group  as  to 
(a)  state,  (6)  color,  (c)  weight,  (d)  chemical  activity. 

23.  Calculate  the  volume  of  hydrochloric  acid  solution, 
density  1.1  and  20  per  cent  pure  acid  by  weight,  that  would 
be  required,  to  neutralize  50  g.  of  Ca(OH)2. 

24.  How  may  Cl  and  HC1  gas  be  obtained,  starting  from 
common  salt  in  each  case  ?    In  what  chemical  way  may 
these  two  substances  be  distinguished  from  each  other  ? 

25.  Give   reasons    why    the    halogens   are    regarded    as 
members  of  a  natural  group  of  elements. 

26.  How  do  you  ascertain  the  properties  of  HC1  and  how, 
in  addition,  could  you  show  that  this  compound  contains 
(a)  hydrogen  ?  (6)  chlorine  ? 

27.  Describe  the  preparation  of  HC1  as  a  by-product  in 
the  manufacture  of  sodium  carbonate.     Give  its  physical 
and  chemical  properties. 

28.  Describe   in   detail   an   experiment   illustrating   the 
bleaching  properties  of  Cl. 

29.  Give  the  important  physical  and  chemical  properties 
of  iodine.    Mention  one  source  and  two  uses  of  iodine. 


44  REVIEW  QUESTIONS  AND  PROBLEMS 

30.  Write  equations  for  the   preparation  of   potassium 
bromide  by  three  different  methods. 

31.  If  a  solution  contains  potassium  bromide  and  potas- 
sium chloride,  how  would  you  show  the  presence  of  the 
halogens  ? 

32.  How  do  you  account  for  the  fact  that  solutions  of 
hydriodic  acid  become  dark  on  standing  some  time  ? 

33.  Write  the  equations  for  the  reactions  of  bromine  with 
zinc,  water,  antimony,  and  hydrogen. 

34.  How  many  liters  of  N  may  be  obtained  by  the  inter- 
action of  Cl  with  NH8? 

35.  If  the  weight  of  1 1.  of  HC1  gas  is  1.735  g.,  what  is 
the  elemental  weight  of  chlorine  ? 

36.  How  many  grams  of  NaCl  are  required  to  prepare 
half  a  kilogram  of  hydrogen  chloride  ? 

37.  The  analysis  of  a  certain  compound  gave  the  following 
results : 

1.  C   =  12.00  per  cent  2.  11.69  per  cent  3.  11.83  per  cent 

H  =    3.98  per  cent  4.02  per  cent  4.00  per  cent 

N  =    6.77  per  cent  6.80  per  cent  6.78  per  cent 

Br  =  77.56  per  cent  77.61  per  cent  77.64  per  cent 

What  was  the  formula  ? 

38.  A  saturated  solution  of  Cl  when  exposed  to   sun- 
light yielded  20  cc.  of  a  gas.    How  would  you  establish 
the  identity  of  the  gas  and  how  much  Cl  was  required  to 
produce  it  ? 

39.  CaO  +  2  NH4C1  =  2  NH8  +  H20  -f  CaCl2.    Given  56 
grains  of  lime,  how  many  cu.  ft.  of  ammonia  at  0°  C.  and 
15  Ib.  pressure  would  result  from  the  above  reaction  ? 

40.  Write  the  formulas   for  the  following  compounds  : 
magnesium  iodide,  mercuric  bromide,  silicon  fluoride,  ferrous 
bromide,  ferric  chloride,  lead  iodide. 


THE  ALKALINE-EARTH  METALS  45 

CHAPTER  XV 
THE  ALKALINE-EARTH  METALS 

1.  What  reaction  takes   place  when  magnesium  flash- 
light powder  is  set  on  fire  ? 

2.  The  gas  density  of  mercury  is  100.    What  is  the  for- 
mula for  the  molecule  ?   Why  is  nitric  acid  a  better  solvent 
for  Hg  than  hydrochloric  ? 

3.  What  is  the  approximate  specific  heat  of  cadmium, 
accepting  112  as  its  atomic  weight  ? 

4.  How  much  Hg  is  formed  by  decomposing  500  g.  of 
cinnabar  ? 

5.  Write  the  formulas  for  the  following  compounds : 
mercuric  sulphate,  mercuric  iodide,  mercurous  bromide,  cad- 
mium sulphate,  cadmium  iodide,  zinc  iodide,  zinc  acetate, 
potassium  zincate,  magnesium   fluoride,  magnesium   phos- 
phate, ammonium  magnesium  phosphate,  magnesium  iodide. 

6.  What  properties  have  the  metals  of  the  magnesium 
family  in  common  with  the  alkali  metals  ?  with  the  alkaline- 
earth  metals  ? 

7.  Distinguish  between  magnesium  chloride  and  magne- 
sium sulphate ;  between  Epsom  salts  and  Glauber  salts. 

8.  What  hydroxide  studied,  other  than  zinc  hydroxide, 
has  both  acid  and  basic  properties  ? 

9.  What  property  of  Mg  is  made  use  of  in  the  isolation 
of  argon  ? 

10.  Erdman  and  Marchand,  in  1844,  obtained  352.4079  g. 
of  mercury  by  heating  380.5744  g.  of  mercuric  oxide.   What 
is  the  atomic  weight  of  mercury  ? 

11.  How  may  quicklime  be  prepared?    What  chemical 
change  takes    place   in   the   drying   of   ordinary  mortar  ? 


46  REVIEW  QUESTIONS  AND  PROBLEMS 

What  substances  ordinarily  cause  temporary  and  perma- 
nent hardness  in  water  ?  Write  the  equation  representing 
the  reaction  involved  in  the  removal  of  temporary  hardness 
by  boiling. 

12.  Name  four  forms  in  which  calcium  carbonate  occurs 
in  nature.  How  may  quicklime  be  prepared  ?  What  happens 
when  water  is  added   to  quicklime  ?    What  is  plaster  of 
Paris  and  from  what  is  it  made? 

13.  What  is  meant  by  radioactivity  ?   What  is  the  pres- 
ent source  of  radium  ?    What  are  the  effects  of  the  rays 
given  off  from  radium  ? 

14.  Explain  in  detail  how  such  elements  as  sodium  and 
calcium  can  be  detected  with  the  aid  of  the  spectroscope. 

15.  The  most  important  ore  containing  mercury  is  cin- 
nabar (HgS).    Where  is   it  found  ?    How  is   the  mercury 
extracted  from  it  ?    What  are  the  commercial  names   of 
inercurous  chloride  and  mercuric  chloride  and  how  do  the 
two  differ  from  each  other  in  chemical  properties  ? 

16.  'xiow  many  grams  of  quicklime  and  how  many  liters 
of  C02  would  be  formed  by  heating  1  kg.  of  limestone  ? 

17.  What    substances    ordinarily    cause    temporary    and 
permanent  hardness  of  water  respectively  ?    Explain  the 
chemistry  involved  in  the  removal  of  temporary  hardness 
and  give  the  equation  expressing  the  reaction. 

18.  What  weight  of  Zn  would  be  required  for  the  pro- 
duction of  sufficient  hydrogen,  at  21° C.  and  745  mm.  pressure, 
to  fill  a  balloon  having  a  capacity  of  100  cc.  ? 

19.  What  weight  of  calcium  carbonate  is  required  to  neu- 
tralize 400  cc.  of  hydrochloric  acid  solution  which  contains 
100  g.  of  the  pure  substance  ? 

20.  A  flask  has  a  capacity  of  15  1.   The  prevailing  temper- 
ature is  18°  C.  and  the  atmospheric  pressure  is  752mm.; 


THE  ALKALINE-EARTH  METALS  47 

what  weight  of  Zn,  reacting  with  H2S04,  would  be  needed  to 
fill  the  flask  with  hydrogen  under  the  prevailing  conditions  ? 

21.  How  is  lime  prepared?    What  is  the  action  of  the 
atmosphere  upon  it  ?    What  is  mortar  ?  How  is  it  prepared 
and  what  chemical  changes  occur  when  it  hardens  ? 

22.  What  is  the  specific  heat  of  cadmium  if  its  atomic 
weight  is  112  ? 

23.  How  much  («)  calomel  can  be  obtained  from  200  g.  of 
mercurous  sulphate  ?   (£>)  how  much  corrosive  sublimate  ? 

24.  Hauer,  in  1868,  found  by  heating  64.2051  g.  of  cad- 
mium sulphate  (CdS04)  that  44.4491  g.  of  cadmium  sulphide 
were  left.   Taking  the  atomic  weights  of  oxygen  and  sulphur 
as  16.00  and  32.06  respectively,  calculate  the  atomic  weight 
of  cadmium. 

25.  Why  is  normal   calcium   phosphate  converted  into 
superphosphate  in  the  manufacture  of  fertilizers  ? 

26.  How  is  a  limekiln  built,  and  why  is  the  production  of 
lime  hastened  by  blowing  air  or  steam  into  the  kiln  ? 

27.  What  is  the  test  for  a  magnesium  compounu  ?   for 
zinc  ?  for  strontium  ?  for  cadmium  ? 

28.  Name  two  alloys  of  zinc  and  state  what  each  contains. 

29.  How  is  zinc  obtained  from  its  ores  ?    Mention  two 
ways  to  prepare  zinc  sulphide. 

30.  Name  a  compound  of  Zn  used  as  a  base  for  paint.  Why 
is  a  zinc  paint  especially  valuable  in  chemical  laboratories  ? 

31.  What  special  name  is  given  to  the  alloys  of  mercury  ? 

32.  How  would  you  test  for  a  soluble  salt  of  Hg  ?    Calcu- 
late the  percentage  composition  of  the  two  chlorides  of  Hg. 

33.  Give  a  method  for  making  zinc  chloride  from  the 
sulphate,  with  equations.   Write  equations  for  the  reactions 
of  a  dilute  solution  of  («)  zinc  bromide,  with  silver  nitrate ; 
(/>)  sodium  hydroxide ;  (c)  chlorine ;  (it)  ammonium  sulphide. 


48  REVIEW  QUESTIONS  AND  PROBLEMS 

34.  Write  equations  showing  four  methods  by  which  the 
salt,  zinc  sulphate,  could  be  made. 

35.  Describe  the  process  of  converting  (a)  limestone  into 
quicklime ;  (6)  quicklime  into  slaked  lime.    Write  the  re- 
action .in  each  case. 

36.  Mention  three  ores  of  zinc.    Describe  the  ordinary 
method  of  extracting  zinc  from  the  ores  mentioned.    Write 
the  reaction. 

37.  Give  the  physical  and  chemical  properties  of  Zn  and 
describe  the  process  of  galvanizing  and  explain  its  use. 

38.  Show  by  equation  how  the  following  compounds  of 
zinc  may  be  obtained  from  metallic  zinc :  the  oxide,  chloride, 
nitrate,  carbonate,  sulphate,  sulphide,  hydroxide. 

39.  Write  the  equation  for  the  reaction  between  barium 
chloride  and  sulphuric  acid  in  (a)  the  ordinary  chemical 
form  and  (6)  the  ionic  form. 

40.  If  64.2508  g.  of  cadmium  sulphate  yield  44.4491  g.  of 
cadmium  sulphide,  what  is  the  atomic  weight  of  cadmium  ? 

41.  How  is  Zn  obtained  in  a  commercial  scale  from  zinc 
ore  ?  Why  is  it  used  for  galvanizing  iron  wire  ?   What  com- 
pound of  Zn  is  used  in  the  manufacture  of  paint?  Define 
the  terms  "alloy"  and  "amalgam"  and  give  an  example 
of  each. 

42.  What  is  meant  by  radioactivity  ?   What  are  alpha, 
and  beta  particles?   Are  they  electrons?   Does  radioactivity 
differ  from  other  chemical  reactions  ? 

43.  Describe,  writing  the  equations  to  express  the  reac- 
tions in  each  case,  the  chemical  changes  that  take  place  in 
the  calcium  compound  from  the  time  it  leaves  the  quarry  as 
limestone  till  it  hardens  into  plaster  on  the  wall. 

44.  Calculate  the  simplest  formula  for  a  compound  having 
the  percentage  compositions  Ca  =  40,  C  =  12,  O  =  48. 


THE  ALKALI  METALS  49 

CHAPTER  XVI 
THE  ALKALI  METALS 

1.  Write  the  formulas  of  the  following  compounds  by 
applying  the  principles  of  valence :  sodium  fluoride,  sodium 
phosphate,  sodium  chlorite,  sodium  acetate,  potassium  man- 
ganate,  acid  potassium  sulphite,  lithium  carbonate,  lithium 
chloride,  lithium  phosphate,  potassium  nitrate,  sodium  sul- 
phate. 

2.  How  much  sodium  will  4  kg.  of  sodium  carbonate 
yield  if  heated  with  carbon  ? 

3.  Describe  the  preparation  of  potassium  hydroxide  from 
potassium  carbonate  and  write  the  reaction.   Give  the  phys- 
ical and  chemical  properties  of  potassium  hydroxide. 

4.  Describe  the  Solway  process  of  manufacturing  sodium 
carbonate.    Write  the  reactions. 

5.  (a)  Mention  two  alkali  metals  and  give  the  formulas 
for  their  hydroxides,  carbonates,  and  sulphates ;  (b)  point 
out  how  these  compounds  differ  in  solubility  from  the  cor- 
responding compounds  of  the  alkali-earth  metals. 

6.  What  is  formed  when  a  solution  of  sodium  hydroxide 
is  saturated  with  hydrogen  sulphide  ? 

7.  Give  a  brief  description  of  making  soda  from  common 
salt  and  making  caustic  soda  from  soda. 

8.  Describe  the  manufacture  of  caustic  soda  from  rock 
salt  according  to  the  electrolytic  process. 

9.  Describe   the   Le   Blanc   process    of  manufacturing 
Na2S04. 

10.  Give  a  complete  description  of  the  action  of  the  metal 
sodium  upon  water.  Give  the  properties  of  the  products  of 
the  action.  Give  a  similar  account  of  potassium. 


50  REVIEW  QUESTIONS  AND  PROBLEMS 

11.  How  many  grams  of  sodium  will  be  needed  to  com- 
bine exactly  with  a  quantity  of  chlorine  which  at  18°  C.  and 
740  mm.  occupied  a  volume  of  200  cc.  ?    What  will  be  the 
weight  of  the  resulting  salt? 

12.  Describe  the  commercial  electrolytic  method  of  ob- 
taining the  metal  sodium  and  write  the  reaction. 

13.  Write  the  equations  for  the 

1.  Action  of  dilute  sodium  hydroxide  on  chlorine. 

2.  Nitric  acid  neutralized  by  potassium  hydroxide. 

14.  Name  the  potassium  salt  and  give  the  formula  for 
each  of  these  acids:  HC1,  HC10,  HC102,  HC103,  HC104, 
HN02,  HN08,  H2S04,  HBr,  HgAsO4,  HF. 

15.  What  weight  of  NaOH  must  be  dissolved  in   1 1. 
of  water  to  yield  a  solution  of  such  strength  that  10  cc.  of 
it  will  exactly  neutralize  5  cc.  of  a  solution  of  HNOg  that 
contains  126  g.  of  the  acid  in  11.? 

16.  Describe  in  detail  what  happens  when  a  solution  of 
sodium  sulphate  is  electrolyzed.    How  may  the  direction 
of  the  current  be  determined  ? 

17.  How  many  kilograms  of  crystallized  sodium  carbonate 
(Na2C08  •  10  H20)  could  be  obtained  from  1000  kg.  of  salt  ? 

18.  What  weight  of  HNOg  would  be  required  to  exactly 
neutralize  30  g.  of  NaOH,  and  what  weight  of  sodium  nitrate 
would  be  formed  ? 

19.  Write  the  equations 

1.  Potassium  and  sulphuric  acid. 

2.  Calcium  hydroxide  and  ammonium  hydroxide. 

3.  Sodium  hydroxide  and  phosphoric  acid. 

4.  Ferric  chloride  and  ammonium  hydroxide. 

20.  Give  the  formulas  for  three  important  compounds  of 
sodium.    How  are  these  compounds  obtained  and  to  what 
use  are  they  put  ? 


THE  ALKALI  METALS  51 

21.  Write  the  formulas  for  the  following  compounds  and 
name  the  acids  of  which  they  are  salts:  sodium  hypochlo- 
rite,  sodium  chlorite,  sodium  chlorate,  sodium  perchlorate, 
sodium  chloride. 

22.  What  is  water  glass  ?    Give  two  uses  to  which  the 
substances  may  be  put. 

23.  How  many  grams  of  potassium  hydroxide  are  con- 
tained  in    11.  of  a  solution   that  6.4  cc.   will   completely 
neutralize  9.6  cc.  of  normal  solution  of  HC1  ? 

24.  How  much  sodic  chloride  may  be  obtained  from  10  g. 
of  crystallized  sodic  carbonate  ? 

25.  To  what  extent  does  the  composition  of  a  pure  chem- 
ical compound  vary  ?    Take  as  an  example  pure  'sodium 
chloride  from  various  sources  and  mention  other  examples 
if  possible. 

26.  Discuss  the  use  of  potassium  compounds  as  a  fertilizer. 
State  the  co'mmon  form  and  its  formula. 

27.  Name  two  compounds  of  sodium  which  are  commonly 
employed  in  the  household  and  give  the  use  of  each. 

28.  What  are  constituents  of  common  gunpowder  ?  What 
is  the  formula  for  caustic  potash  ? 

29.  How  may  Na2COg  •  10  H20  be  converted  into  NaOH, 
and  how  may  metallic  sodium  be  made  from  NaOH  ?    Give 
reactions. 

30.  Give  the  tests  for  sodium  ;  for  potassium  ;  for  lithium. 

31.  Explain    the    formation    of    potassium    nitrate   by 
nitrification. 

32.  In  what  location  are  sodium,  potassium,  and  lithium 
produced  in  nature  ? 

33.  Give  the  chemical  difference  between  sodium  carbon- 
ate and  sodium  bicarbonate.  What  are  their  common  names 
and  their  uses  ? 


52  REVIEW  QUESTIONS  AND  PROBLEMS 

34.  If  a  gram  of  gunpowder  produces  300  cc.  of  gas  at 
O°  C.,  what  will  its  volume  be  at  2000°  C.  ? 

35.  Give   the    important    compounds    of  lithium ;   their 
properties  and  uses.    Give  the  properties  of  lithium. 

36.  Name  all  the  members  of  this  group  and  compare 
them  as  to  common  characteristics. 

37.  Which  of  these  gases  would  you  dry  with  solid  caustic 
potash :  oxygen,  carbon  dioxide,  ammonia,  carbon  monoxide  ? 

38.  How  would  you  prove  the  presence  of  potassium  in 
plants  ? 

39.  Distinguish  by  analysis  between  sodium  chloride  and 
ammonium  chloride. 

40.  How  would  you  distinguish  between  KF,  KI,  Kl>r, 
KC1? 

41.  Why  does  KHS04  react  acidic,  while  NaHCO8  reacts 
alkaline  ? 

42.  Sodium  nitrate  is  used  in  the  preparation  of  H]^()3. 
Why  not  potassium  nitrate  ? 

43.  How  could  you  prove  that  the  water  in  crystals  of 
NaCl  is  not  water  of  crystallization  ? 


CHAPTER  XVII 
ALUMINUM-BORON  GROUP 

1.  How  is  aluminum  obtained  ?    Is  the  method  of  elec- 
trolysis used  in  decomposing  the  more  stable  or  the  less 
stable  compounds  ? 

2.  What  care  must  be  taken  of  kitchen  utensils  made  of 
aluminum  ? 

3.  (a)  How  could  you  prove  that  alum  contains  alumi- 
num ?  (U)  What  are  the  properties  of  aluminum  ? 


ALUMINUM-BORON  GROUP  53 

4.  Explain  why  alum  turns  litmus  red  and  borax  turns 
litmus  blue. 

5.  What  is  the  per  cent  of  aluminum  in  (a)  cryolite 
(Na8AlF6)?  (ft)  in  turquoise  (Al^O,  •  H8A1206  •  2  H2O)? 

6.  Write  the  formulas  for  aluminum  sulphide,  aluminum 
phosphate,  aluminum  acetate,  potassium  aluminate. 

7.  Write  the  equation  to  show  how  aluminum  hydroxide 
can  play  the  part  of  a  base ;  of  an  acid. 

8.  What  compound  of  aluminum  is  formed  when  a  solu- 
tion of  calcium  carbonate  reacts  with  a  solution  of  aluminum 
sulphate  ? 

9.  Describe  briefly  the  commercial  process  for  the  prepa- 
ration of  aluminum  from  aluminum  oxide. 

10.  Give  the  properties  of  metallic  aluminum  and  the 
name  and  formula  of  an  important  salt. 

11.  How  many  grams  of  aluminum  can  be  obtained  from 
200  kg.  of  bauxite  (A1208  -  2  H20)  ? 

12.  Describe  the  reaction  that  takes  place  between  metallic 
aluminum  and  ferric  oxide  when  a  mixture  is  ignited.    Give 
the  equation  and  state  what  practical  applications  are  made 
of  the  reaction. 

13.  Describe  in  detail  the  Goldschmidt  process  for  weld- 
ing iron,  giving  the  equation  expressing  the  reaction. 

14.  («)  Complete  and  balance  the  following: 

1.  Ala(S04)8  +  KOH=  3.  A1(OH)8  +  HC1  = 

2.  Al  (OH),  +  KOH  =  4.  AgN08  +  KBr  = 

(i)  Is  aluminum  hydroxide  to  be  regarded  as  an  acid  or 
as  a  base? 

15.  What   is   the   composition   of    the   mixture   termed 
"  thermit "  ?    What  is  the  chemical  action  that  takes  place 
between  these  components  ?    What  practical  use  is  made  of 
thermit  ? 


54  REVIEW  QUESTIONS  AND  PROBLEMS 

16.  Explain  the  use  of  aluminum  sulphate  in  the  purifi- 
cation of  water. 

17.  Having  solutions  of  magnesium  sulphate,  cadmium 
chloride,  and  aluminum  sulphate,  how  would  you  test  for 
the  metallic  ions  ?    What  is  a  mordant  ? 

18.  What  are  the  products  obtained  by  heating  sodium 
sulphate  with  boracic  acid? 

19.  How  many  grams  of  C02  are  evolved  when  200  g.  of 
borax  are  made  by  the  interaction  of  boric  acid  and  Na2CO3  ? 

20.  Which  contains  the  larger  percentage  of  boron  —  boric 
acid,  boracic  acid/  or  boron  trioxide  ? 

21.  What  is  the  formula  for  ferric  ammonium  alum  and 
what  are  its  properties  and  uses  ? 

22.  Terreil,   in    1879,  found  that   0.0455  g.  of  H  was 
evolved  when  0.410  g.  of  aluminum  was  dissolved  in  an 
acid.    What  is  the  atomic  weight  of  aluminum  calculated 
from  this  experiment  ? 

23.  What  hydroxides  other  than  aluminum   hydroxide 
have  both  acid  and  basic  properties  ? 

24.  Write  the  equations  for  the  preparation  of  aluminum 
hydroxide  and  aluminum  sulphate. 

25.  Write  the  general  formula  of  an    alum,  letting  M 
represent  the  atom  of  the  alkali  metal  and  X  the  atom  of 
the  trivalent  metal. 

26.  In  what  respect  does  aluminum  oxide  differ  from  cal- 
cium oxide  in  properties  ? 

27.  Explain  the  use  of  borax  for  the  "  softening  of  water" ; 
the  use  of  it  in  the  "  borax  bead's  "  test. 

28.  How  could  Al,  NH4,  and  S04  be  recognized  in  an  alum 
solution  ?  Illustrate  with  equations. 

29.  What  volume  of  0  at  15°  C.  and  760  mm.  is  needed  to 
change  8  Ib.  of  aluminum  into  aluminum  oxide  (A12O8)  ? 


IRON,  NICKEL,  COBALT,  PLATINUM  GROUP      55 

CHAPTER  XVIII 
IRON,  NICKEL,  COBALT,  PLATINUM  GROUP 

1.  Does  iron  occur  free  in  nature  ?   Give  the  reason. 

2.  Name  and  compare  the  three  varieties  of  iron.    Why 
should  these  not  be  regarded  as  allotropic  forms  ? 

3.  There  are  two  metallurgical  processes.  Iron  illustrates 
one  and  sodium  the  other.    Describe  each  process. 

4.  Describe  the  manufacture  of  iron  in  the  blast  furnace. 

5.  Describe  in  detail  the  manufacture  of  pig  iron  from 
iron  ore. 

6.  Give  the  tests  for  iron. 

7.  Name  at  least  three  iron  ores.    Describe  the  manu- 
facture of  cast  iron.    What  is  the  flux  generally  used  in 
smelting  iron  ?   Name  the  chief  chemical  changes  that  take 
place  in  a  blast  furnace.    How  is  cast  iron  converted  into 
wrought  iron  and  steel  ? 

8.  How  is  steel  made  from  pig  iron  by  the  Bessemer 
process  ? 

9.  Name  an  ore  of  each  of  the  following  metals :  iron, 
lead,  zinc,  and  mercury.    Give  a  test  for  a  metal  in  each  of 
the  following  ways :    (a)  by  flame  coloration ;  (£)  by  the 
borax  bead ;  (e)  by  the  blowpipe  in  charcoal. 

10.  How  may  a  ferrous  salt  be  prepared?    a  ferric  salt? 
Give  a  special  test  for  each. 

11.  Name   the  ingredients  of   the  furnace   charge  that 
would  be  employed  in  the  manufacture  of  cast  iron  from  an 
ore  containing  ferric  oxide  mixed  with  sand.    Make  a  dia- 
gram of  the  furnace. 

12.  What  weight  of  0  is  required  to  unite  with  21  g.  of 
iron  to  give  the   magnetic  oxide  of  iron  (Feg04)?    What 
volume  will  this  0  occupy  at  10°  C.  and  750  mm.  ? 


56  REVIEW  QUESTIONS  AND  PROBLEMS 

13.  Give  the  names  of  the  different  processes  for  produc- 
ing steel   from  cast  iron,  and  define  ore  and  flux.    Give 
formulas  for  six  important  compounds  of  iron. 

14.  How  would  you  (a)  make  ferrous  chloride  from  iron  ? 
(6)  ferrous  sulphide  from  ferrous  chloride  ?    (c)  ferrous  sul- 
phate from  ferrous  sulphide  ?    (d)  ferric  hydroxide   from 
ferrous  sulphate  ? 

15.  In  the  above  question  write  the  equations  for  the  re- 
actions after  giving  the  descriptions  of  the  processes,  and 
indicate  the  color  of  the  product  in  each  case. 

16.  How  can  ferrous  sulphate  be  made  from  iron  and  this 
compound  converted  into  a  ferric  salt  ?    How  would  you  test 
for  ferric  oxide  in  the  solution  ? 

17.  Both  iron  and  aluminum  become  oxidized  upon  ex- 
posure to  the  air.    Why  does  iron  gradually  disintegrate, 
and  why  does  aluminum  remain  not  perceptibly  changed  ? 

18.  Why  is  iron  pyrites  an  objectionable  ore  from  which 
to  obtain  iron  ? 

19.  Russell,  in  1869,  found  that  the  hydrogen  produced 
by  the  action  of  HC1  upon  cobalt  was  3.4917  per  cent  of 
the  metal.    Calculate  the  atomic  weight  of  cobalt. 

20.  Write  the  formulas   for  the  following  compounds : 
potassium  ferrocyanide,  potassium  ferricyanide,  ferric  ferro- 
cyanide,  ferrous  ferricyanide,  potassium  cobalt  nitrite,  ferric 
acetate,  ferric  nitrate,  ferrous  bromide,  nickelic  sulphate, 
cobaltic  nitrate. 

21.  Write  the  chemical  and  ionic  equations  for  the  displace- 
ment of  copper  by  iron  in  solutions  of  copper  compounds. 

22.  What  is  a  slag?    How  is  it  produced  and  what  is 
its  use? 

23.  What  is  the  method  of  preparation  of  platinum,  and 
what  metal  is  likely  to  be  alloyed  with  it  ? 


COPPER,  SILVER,  AND  GOLD  GROUP  57 

24.  When  a  solution  of  sodium  carbonate  is  added  to  a 
solution  of  a  ferric  salt,  an  hydroxide  is  precipitated  and 
not  a  carbonate.    How  is  this  explained  ? 

25.  Give  the  tests  for  nickel  and  cobalt. 

26.  What  is  the  only  important  compound  of  platinum, 
and  what  is  the  use  of  platinum  in  the  contact  process  in 
the  manufacture  of  H2S04? 

27.  Distinguish  between  chrome  iron,  nickel  steel,  spiegel 
iron,  and  vanadium  steel. 

28.  What  is  the  minimum  weight  of  carbon  per  ton  of 
steel   that  can  be  added  and  yet  have  the  steel  take  a 
temper  ? 

29.  Describe  the  open-hearth  process ;  the  Siemens-Martin 
process  of  manufacturing  steel. 

30.  State  the  most  important  uses  of  cobalt,  its  properties, 
and  how  and  when  found. 

31.  Give  the  chemical  and  the  common  name  of  FeS. 
How  can  it  be  prepared  in  the  laboratory  ?    Give  equation. 


CHAPTER  XIX 
COPPER,  SILVER,  AND  GOLD  GROUP 

1.  Compare  copper,  silver,  and  gold  in  their  physical 
and  chemical  properties. 

2.  What  is  oxidized  silver,  German  silver,  sterling  silver? 

3.  Write  the  formulas  for  the  following  compounds : 
cuprous  nitrate,  cupro'us  sulphide,  cuprous  iodide,  cupric 
acetate,  silver  cyanide,  silver  sulphate,  silver  oxide,  aurous 
bromide,  auric  chloride,  aurous  hydroxide,  cupric  hydroxide. 

4.  If  500  g.  of  silver  interact  with  nitric  acid,  how  much 
silver  nitrate  is  formed? 


58  REVIEW  QUESTIONS  AND  PROBLEMS 

5.  Write  the  equation  for  the  reduction  of  cupric  oxide 
by  hydrogen  with  heat. 

6.  What  acid  would  you  use  to  dissolve  silver  ?    What 
chemical  test  would  show  the  difference  between  a  solution 
containing  a  silver  salt  and  one  containing  a  zinc  salt  ? 
Write  equations  to  illustrate  both  answers. 

7.  Write  equations  for  the  reaction  between  silver  and 
nitric  acid  ;  also  for  the  resulting  solution  with  hydrochloric 
acid.    Describe   the    visible    changes    accompanying    these 
reactions. 

8.  Describe  a  process  of  obtaining  copper  from  one  of 
its  ores.    Mention  (</)  the  properties  of  copper,  and  (6)  the 
important  uses. 

9.  Write  the  equation  for  the  reaction  of   H2SO4  on 
copper   when    heated.    Explain    why  the  gaseous  product 
obtained  differs  from  that  usually  produced  by  the  action 
of  an  acid  on  a  metal. 

10.  Define  cupellation.    Describe  a  process  of  extracting 
silver  from  its  ores  by  cupellation. 

11.  Calculate  the  percentage  of  water  of  crystallization 
in  crystalline  copper  sulphate  (CuS04  •  5  H2O). 

12.  An  experiment  showed  that  when  2.16  g.  of  silver 
were  treated  with  chlorine  2.87  g.  of  silver  chloride  were 
formed.    Calculate  from  this  result  the  atomic  weight  of 
silver. 

13.  Describe  experiments  by  which  you  could  determine 
.  whether  or  not  an  alloy  contained  silver. 

14.  Name  the  elements  that  enter  into  the  composition 
of  the  following  alloys,  and  give  the  usual  percentage  rela- 
tion :  («)  aluminum  bronze  ;  (/>)  brass  ;  (c)  bronze  ;  (d)  Ger- 
man silver ;  (e)  gold  coin ;  (/)  gun  metal ;  (</)  nickel  coin  ; 

A    silver  coin. 


COPPER,  SILVER,  AND  GOLD  GROUP  59 

15.  How  could  you  prepare  pure  silver  chloride  from  a 
silver  coin  ? 

16.  Account  for  the  action  of  sulphur  water  and  eggs 
upon  silver. 

17.  Silver  may  be  cleaned  by  boiling  it  in  water  in  an 
aluminum  vessel.  Write  .the  equation  for  the  action  involved. 

18.  Silver  nitrate  and  mercuric  nitrate  are  both  white  salts 
soluble  in  water.   How  could  you  distinguish  between  them  ? 

19.  Describe,    giving   chemical    reactions    involved,   the 
amalgamated  process  of  refining  silver.    Why  is  the  silver 
sulphide  first  changed  into  silver  chloride  ? 

20.  Why  is  silver  not  used  as  an  electric  conductor  ? 

21.  Describe  what  takes  place  when  a  solution  of  silver 
nitrate  is  electrolyzed  (a)  with  both  terminals  of  platinum ; 
(A)  with  both  terminals  of  silver. 

22.  What  occurs  when  a  solution  of  copper  sulphate  is 
electrolyzed  (a)  with  both  electrodes  of  copper  ?  (b)  with 
both  electrodes  of  platinum  ? 

23.  («.)  Describe  the  electrolytic  purification  of  copper; 
(fi)  the  method  of  electrolytic  copperplating. 

24.  What  chemical  compound  is  ordinarily  employed  in 
photography  ?  Describe  briefly  the  chemistry  of  the  different 
steps  taken  in  making  a  photograph. 

25.  Draw  carefully  a  diagram  of  an  apparatus  for  passing 
H  over  red-hot  oxide  of  copper.    Include  the  details  for  mak- 
ing the  hydrogen  gas  and  the  arrangement  for  preserving 
separately  the  products  of  the  reaction. 

26.  State  two  ways  by  which  an  aqueous  solution  of  a 
copper  salt  may  be  distinguished  from  one  of  a  ferric  salt. 

27.  Why  is  plated  ware  softer  than  sterling  silver?   What 
compound  is  usually  formed  when  silver  tarnishes  ?  Mention 
two  articles  of  food  that  cause  silver  to  tarnish. 


60  REVIEW  QUESTIONS  AND  PROBLEMS 

28.  How  does  copper  occur  in  nature  ?    What  is  blue 
vitriol  ?    Give  three  tests  for  copper. 

29.  If  4.393  g.  of  copper  precipitate  14.91  g.  of  silver 
from  a  silver  nitrate  solution,  and  the  atomic  weight  of 
silver  is  108,  what  is  the  atomic  weight  of  copper  ? 

30.  How  would  you  account  for  the  fact  that  solutions  of 
the  different  salts  of  a  metal  usually  have  the  same  color  ? 

31.  How  would  you  test  for  the  presence  of  silver  in 
an  ore? 

32.  From  10  cc.  of  a  solution  of  silver  nitrate  0.9365  g. 
of  silver  chloride  were  obtained  by  precipitation  with  hydro- 
chloric acid.  How  many  grams  of  silver  nitrate  are  contained 
in  a  liter  of  the  solution  ? 

33.  Describe  the  chlorination  and  the  cyanide  processes 
for  extracting  gold. 

CHAPTER  XX 
CHROMIUM  AND  MANGANESE  GROUP 

1.  Name  the  members  of  the  chromium  group. 

2.  Distinguish     between     trivalent     and     hexavalent 
chromium. 

3.  Name  the  most  important  compounds  of  chromium. 

4.  Give   the   equation   for   the  action  of  H2SO4  upon 
potassium  chromate,  showing  all  steps. 

5.  How   is   permanganate  solution  used  as  a  test  for 
organic  matter  in  water  ? 

6.  Name  (a)  the  most  important  compounds  of  man- 
ganese ;  (7>)  state  their  uses ;  (e)  give  their  characteristics. 

7.  In   the  preparation    of   0    from   KC10g   manganese 
dioxide  is  used.    Explain  its  action  and  name  the  process. 


CHROMIUM  AND  MANGANESE  GROUP  61 

8.  How  may  potassium  dichromate  be  converted  into 
potassium  chromate  and  vice  versa? 

9.  What  is  chrome  iron,  and  what  is  the  purpose  in 
using  chromium  in  iron  ? 

10.  Give  the  tests  for  Mn  and  for  chromium. 

11.  Write  the  equations  for  the  following  reactions: 

1.'  Preparation  of  manganous  chloride. 

2.  Preparation  of  manganous  hydroxide. 

3.  Ferrous  sulphate  +  potassium  permanganate  = 

4.  Ammonium  sulphate  -f-  chromium  sulphate  = 

5.  Potassium  chromate  +  hydrochloric  acid  = 

12.  How  many  grams  of  lead  chromate  can  be  made  from 
500  g.  of  potassium  dichromate  ? 

13.  Why  is  chrome  alum  called  a  double  salt?    What  is 
the  meaning  ? 

14.  How  is  manganese  classified  in  the  groups  of  the 
elements  ? 

15.  Describe  the  use  of  manganese  in  the  manufacture  of 
Cl  by  the  Welden  process,  and  give  the  reactions. 

16.  What    is    known    of    molybdenum,    tungsten,    and 
uranium  ? 

17.  What  is  meant  by  the  term  "  catalysis "  ?    Give  a 
reaction  in  which  a  catalytic  agent  is  used. 

18.  What   evidence   is   there    from   the   study  of  chro- 
mium and  its  compounds  that  oxygen  is  correctly  called 
acid  former  ? 

19.  How  does  K2Cr207  prevent  the  "polarization"  of  a 
voltaic  cell  ?    What  chromium  compound  is  formed  in  the 
"  dichromate  "  battery  ? 

20.  Exactly  20  cc.   of  a  solution   containing   15.8  g.  of 
KMnO4  per  liter  were  needed  to  react  completely  with  a 
solution  of  H./Xr    How  much  H202  was  there  ? 


62  REVIEW  QUESTIONS  AND  PROBLEMS 

CHAPTER  XXI 
ORGANIC  ACIDS  AND  COMPOUNDS 

1.  What  are  hydrocarbons  and  where  are  they  found  in 
nature  ?    Name  some  hydrocarbons  which  occur  in  illumi- 
nating gas,  and  show  how  you  would  prepare  any  one  of 
them.    Give  the  equations. 

2.  What  volume'  of  ordinary  air  would  be  required  for 
the  complete   combustion   of  15 1.  of  methane,  and  what 
weight  of  C02  would  be  formed  ? 

3.  State  two  physical  properties  of  acetylene.    Why  does 
it  give  out  light  when  burned  in  the  air  ?    Explain   the 
structure  and  principle  of  the  acetylene  burner  designed  to 
prevent  the  gas  from  burning  with  a  smoky  flame.    What 
two  products  of  combustion  are  formed  when  the  gas  burns 
in  air  ?    How  may  the  presence  of  each  be  detected  ? 

4.  What  is  the  essential  character  of  the  common  animal 
fats  ?    Explain  the  process  of  soap  making.    What  is  the 
difference  between  "  hard  "  and  "  soft "  soaps  ? 

5.  Determine  the  molecular  formula  for  a  compound  made 
up  as  follows  :  carbon  80  per  cent ;  hydrogen  20  per  cent ; 
vapor  density  15. 

6.  The  formula  for  ethane  is  C2H6.   Calculate  the  specific 
gravity  of  its  vapor  (a)  compared  with  hydrogen  ;  (6)  com- 
pared with  air. 

7.  Find  the  proportions  by  weight  and  by  volume  in 
which  ethane  gas  (C2Hg)  will  combine  with  oxygen. 

8.  What  is  a  soap  ?  Name  two  soaps  soluble  in  water ;  one 
not  soluble  in  water.    Describe  a  process  for  making  soap. 

9.  Mention  (a)  four  hydrocarbons ;  (i)  four  carbohydrates. 
Write  the  formula  of  each  compound  mentioned. 


ORGANIC  ACIDS  AND  COMPOUNDS  63 

10.  Describe  an  experiment  to  show  the  presence  of  each 
of  the  following  in  kerosene  oil :  («)  carbon ;  (/>)  hydrogen. 

11.  Mention  three  organic  acids.    State  the  physical  and 
chemical  properties  of  each. 

12.  Find  the  weight  of  each  of  the  products  of  combus- 
tion of  52  g.  of  camphene  (CJOH16). 

13.  Describe  a  method  of  preparing  sulphuric  (common) 
ether,  and  mention  its  properties  and  uses. 

14.  Describe  the  changes  that  take  place  when  grape 
juice  undergoes  («)  alcoholic  fermentation;  (/<•)  acetic  fer- 
mentation, and  write  the  reaction  in  each  case. 

15.  Write  the  graphic  formula  for  marsh  gas  and  find  its 
percentage  composition. 

16.  Compare  common  (ethyl)  alcohol  with  wood  spirit 
(methyl)  alcohol  as  to  («)  sources ;  (6)  important  properties 
and  uses. 

17.  Name  the  three  classes  of  carbohydrates  and  write 
the  chemical  formula  for  each. 

18.  How  would  you  bring  about  the  alcoholic  fermenta- 
tion of  grape  sugar  ?    Write  the  equation.    Give  a  test  for 
each  of  the  products  of  the  fermentation. 

19.  Write  the  chemical  formulas  for  the  following  com- 
pounds :  iodoform,  wood  alcohol,  formaldehyde,  ether,  acetic 
acid,  starch,  chloroform. 

20.  Describe   cane   sugar   and  acetic  acid,  touching  on 
(a)  production ;  (/>)  physical  properties ;  (c)  chemical  prop- 
erties ;  ((F)  chemical  formula. 

21.  Describe  the  manufacture  of  wood  alcohol,  and  state 
its  properties  and  uses. 

22.  Explain  the  instability  of  organic   substances   and 
state  its  importance  in  (</.)  nature;  (b)  fuels. 


64  REVIEW  QUESTIONS  AND  PROBLEMS 

23.  State  the  eight  divisions  of  organic  compounds,  and 
give  the  important  members  of  each. 

24.  Compare  isomerism  and  allotropy,  and  give  examples 
of  each. 

25.  What  is  saponification,  and  how  is  it  illustrated  ? 

26.  Explain  how  collodion  is  related  to  cellulose. 

27.  Explain   the   relation   of   methyl   chloride  to  wood 
alcohol.    How  is  methyl  chloride  used  in  surgery  ? 

28.  Write  the  equation  expressing  the  reaction  that  takes 
place  when  formaldehyde  is  prepared  from  wood  alcohol. 
State  the  relation  between  formaldehyde  and  formalin. 


CHAPTER  XXII 
EQUATIONS  AND  GENERAL  FORMULAS 

1.  Give  the  formulas  for  borax,  lime,  quartz,  green  vitriol, 
caustic  soda,  carborundum,  marble,  plaster  of  Paris,  pyrite, 
and  cinnabar. 

2.  Give  the  name,  formula,  method  of  preparation,  and 
use  of  each  of  two  carbides  extensively  used. 

3.  Classify  as  acids,  bases,  or  salts,  and  give  name  of 
each:    NaOH,   HF,    NaOCl,    KC108,   NaHC08,    NH4N03, 
NH4OH,  K2S04,  Ca(OH)2,  HN02. 

4.  Complete  the  following  equations,  using  formulas  : 

1.  Barium  chloride  +  sodium  sulphate  = 

2.  Hydrogen  sulphide  +  bismuth  chloride  = 

3.  Ammonium  chloride  +  calcium  oxide  — 

4.  Sulphur  dioxide  +  chlorine  +  water  = 

5.  Give  the  name  and  formula  of  a  binary  compound,  an 
acid  containing  oxygen,  a  base,  and  a  normal  salt. 


EQUATIONS  AND  GENERAL  FORMULAS         65 

6.  Give  the  chemical  name  of  each  of  the  following  sulv 
stances  :  calomel,  brimstone,  fire  damp,  choke  clamp,  muriatic 
acid,  oil  of  vitriol,  copperas. 

7.  Complete,  using  formulas  : 

1.  Nitric  acid  -f  sodium  carbonate  = 

2.  Ammonium  chloride  +  caustic  soda  = 

3.  Water  +  metallic  sodium  = 

4.  Manganese  dioxide  +  hydrochloric  acid  = 

8.  Give  a  chemical  method  of  distinguishing  between 
each  of  the  following: 

1.  Hydrogen  and  carbon  monoxide. 

2.  Hydrogen  chloride  and  sulphur  dioxide. 

3.  Oxygen  and  nitrous  oxide. 

4.  Nitrogen  and  carbon  dioxide. 

9.  Classify  these  compounds  under  the  headings  (a)  acids, 
(&)  bases,  (c)  normal  salts,  (d)  acid  salts,  (e)  anhydrides, 
(/)  oxides:  CO2,  NaHS04,  CaCl2,  PbO,  H8P04,  Ca(OH)2, 
NaSO8,  Mn02,  S02,  KC1,  KHS04,  NH4OC1,  NaOH,  CaF2, 
HI,  NH4OH,  Ca(C10,)a,  NaN08. 

10.  Complete  the  following  equations,  using  symbols  and 
formulas : 

1.  Ammonium  hydroxide  +  hydrochloric  acid  = 

2.  Ammonia  +  hydrochloric  acid  = 

3.  Sodium  chloride  +  silver  nitrate  = 

4.  Ferrous  sulphide  +  sulphuric  acid  = 

5.  Lead  nitrate  +  hydrogen  sulphide  = 

6.  Manganese  dioxide  +  hydrochloric  acid  = 

7.  Calcium  carbide  +  water  = 

8.  Arsenic  trioxide  -f  nascent  hydrogen  = 

9.  Sodium  carbonate  +  nitric  acid  = 

10.  Calcium  hydroxide  +  carbon  dioxide  = 


66  REVIEW  QUESTIONS  AND  PROBLEMS 

11.  Complete  and  balance  : 

1.  A12(S04)3  +  KOH  =          3.  A1(OH)3  +  HC1  = 

2.  Al  (OH),  +  KOH  =  4.  AgN08  +  KBr  = 

5.  CaCO8  +  C02  +  H20  = 

12.  Give  chemical  names  and  molecular  formulas  for  the 
following :  borax,  Epsom  salts,  Glauber  salts,  white  vitriol, 
green  vitriol,  blue  vitriol,  iron  pyrites,  hematite,  magnetite, 
potash,  galena,  alum,  gypsum,  and  cryolite. 

13.  Classify  as  acids,  bases,  or  salts,  and  name :   H2S04, 
KC1,  KHS04,  NH4OC1,  NaOH,  CaF2,  HI,  NH4OH,  Ca(C108)2, 
NaN08. 

14.  For  what  do  the  following  symbols  and  formulas  stand : 
S02,  C,  CH4,  Fe08,  CO2,  CaCO3,  Hg,  I2,  H3P04,  NaOH,  (OH), 
(NH4),  NH3,  Ag,  Al,  03,  S.,  As/).,  SnO2,  and  Pb(OH)2? 

15.  Complete  and  balance : 

1.  NaOH  +  H2S04  =  3.  Na  +  HaO  = 

2.  Mg  +  HC1  =  4.  NaN03  +  NH4C1  +  II.  E.  = 

5.  NaCl  +  Mn()2  +  H2S04  +  H.  E.  = 
NOTE.    H.  E.  stands  for  heat  energy. 

16.  Write  the  formulas  for  the  following  compounds  and 
name  the  acids  of  which  they  are  salts :  sodium  hypochlorite, 
sodium  chlorite,  sodium  chlorate,  sodium  perchlorate,  sodium 
chloride. 

17.  Give  the  names  of  the  following  acids  and  of  the 
sodium  salt  of  each:  HC1,  HC10,  HC102,  HC103,  HC104, 
HNO2,  HN08,  HBr,  HI,  HF. 

18.  Write  the  equations  for  the  following  reactions : 

1.  Silver  nitrate  and  sodium  chloride. 

2.  Aluminum  sulphate  and  potassium  hydroxide. 

3.  Ammonium  chloride  and  slaked  lime. 

4.  Sodium   chloride,   manganese   dioxide,   and    sul- 

phuric acid. 


EQUATIONS  AND  GENERAL  FORMULAS          67 

5.  Sodium  hydroxide  and  sulphuric  acid. 

6.  Chlorine  and  potassium  bromide. 

7.  Steam  and  incandescent  coke. 

8.  Calcium  carbide  and  water. 

9.  Calcium  hydroxide  and  carbon  dioxide. 
10.  Methane  and  oxygen  (ignited). 

19.  Write  the  equations  for  the  reactions  between  the 
following  substances : 

1.  Calcium  carbonate  and  hydrochloric  acid. 

2.  Potassium  nitrate  and  sulphuric  acid. 

3.  Copper  and  water  vapor  (heated). 

4.  Aluminum  sulphate  ancPammoiiiuiu  hydroxide. 

5.  Calcium  carbide  and  water. 

20.  Write  the  formulas  for  the  following : 

1.  Potassium  chloride.  6.  Ferrous  sulphide. 

2.  Sodium  carbonate.  7.  Ferric  chloride. 

3.  Phosphoric  acid.  8.  Aluminum  sulphate. 

4.  Sodium  cyanide.  9.  Cuprous  oxide. 

5.  Ferric  oxide.  10.  Manganese  dioxide. 

21.  Write  the  equations  for  the  following  reactions: 

1.  Potassium  hydroxide  and  sulphuric  acid. 

2.  Calcium  hydroxide  and  sulphuric  acid. 

3.  Calcium  hydroxide  and  ammonium  sulphate. 

4.  Ferric  chloride  and  ammonium  hydroxide. 

5.  Sodium  hydroxide  and  phosphoric  acid. 

6.  Ammonium  nitrate  and  heat. 

22.  Write  the  formulas  for 

1.  Sodium  carbonate.  4.  Arsine. 

2.  Lead  sulphate.  5.  Arsenic  trioxide. 

3.  Silica.  6.  Ammonium  sulphide. 

7.  ^Normal  c;ilcium  phosphate. 


68  REVIEW  QUESTIONS  AND  PROBLEMS 

23.  Write  the  formulas  for 

1.  Limestone.  5.  Aluminum  phosphate. 

2.  Secondary  sodium  phos-        6.  Mercurous  chloride. 

phate.  7.  Barium  nitrate. 

3.  Cupric  sulphate.  8.  Acetylene. 

4.  Ammonia.  9.  Gypsum. 

10.  Marsh  gas. 

24.  Classify  as  acids,  bases,  or  salts:  NaN08,  NH4C1, 
HC10,  NH4OH,  BaS04,  Ca(NO8)2,  HC104,  Sr(OH)2,  HN02, 
Fe(OH)8. 

25.  Write  the  formulas  for 

1.  Barium  perchlorate.  6.  Sodium  perchlorate. 

2.  Ammonium  sulphate.  7.  Calcium  hypochlorite. 

3.  Strontium  nitrate.  8.  Barium  hydroxide. 

4.  Calcium  sulphate.  9.  Strontium  oxide. 

5.  Ferric  sulphate.  10.  Barium  nitrate. 

26.  Complete  and  balance  : 

1.  CaC03  +  HC1  =  6.  Mn02  +  NaC  1  +  H2S04  = 

2.  Mn02  +  HCl=  7.  Zn  +  H2S04  = 

3.  A12(S04)8  +  NH4OH  =  8.  CaC2  +  H20  = 

4.  CuS04  +  H2S  =  9.  H20  +  C  (hot)  = 

5.  KOH  +  H8P04  =  10.  Cl  +  KOH  = 

11.  FeCl8  +  NH4OH  = 

27.  Give  the  structural  formulas  of  NH4C1,  NH4OH,  and 
(NH4)2S04. 

28.  Complete  and  balance : 

1.  Na2C08  +  HC1  =  6.  Ca,(P04)2  +  H2S04  = 

2.  CaC08  +  HN08  =  7.  NaOH  +  H3P04  = 

3.  A12(S04)8  +  KOH  =  8.  KN08  +  H2SO4  = 

4.  Zn  +  H2S04=  9.  Mn02  +  HC1  = 

5.  CuS04  +  H2S=  10.  SCyNCyOH  +  H20  = 


EQUATIONS  AND  GENERAL  FORMULAS          69 

29.  Write  the  formulas  for 

1.  Marble.  6.  Ammonium  phosphate. 

2.  Primary  sodium  sulphate.    7.  Ammonia. 

3.  Aluminum  sulphate.  8.  Silver  nitrate. 

4.  Cuprous  chloride.  9.  Mercuric  chloride. 

5.  Cupric  oxide.  10.  Quicklime. 

30.  Name  the  following:  (NH4)2C08,  NH4HOOg,  NH4CN, 
NH4H2P04,  Au20g,  Ba(C2H802)2,  BaCr04,  BiBrs,  BiON08, 
CsCl,  NiAs,  Os04,  K2A12O4,  K2PtCl4,  FeAs04-2H20. 

31.  Name  the  following:  NiS2,  NaHC08,  NaAuCl4  •  2  H2O, 
SeCl2,  RuCl2,  CaAlSi2O8,  SnF2,  SrC2,  TaBrfi. 

32.  Name  the  following:  NaC104,   HC1O,  NO,   KC1O2, 
KN02,  C.N,,  H2S04,  H2S8O4,  H8PO4,  HNaC08,  Ca(OCl), 
FeCl8,  CuBr,  HKC08,  NH4C1,  Ca(OH)2,  H202,  H8P08,  C2H2. 

33.  Complete  the  following  reactions,  using  formulas  : 

1.  Iron  +  sulphuric  acid  = 

2.  Zinc  oxide  +  nitric  acid  = 

3.  Calcium  hydroxide  +  carbon  dioxide  = 

4.  Marsh  gas  +  oxygen  (ignited)  = 

5.  Hydrogen  sulphide  +  lead  nitrate  = 

34.  Classify  into  acids,  bases,  salts,  or  anhydrides :  S08, 
NaN08,   HBr,    Ba(OH)3,   CaS04,   P2O5,   H8BO3,   NH4OH, 
H8P04,  C02. 

35.  Complete,  using  formulas  : 

1.  Ferrous  sulphate  -f  hydrochloric  acid  = 

2.  Calcium  carbonate  -f-  nitric  acid  = 

3.  Sulphurous  acid  +  sodium  hydroxide  = 

4.  Silver  nitrate  +  potassium  bromide  = 

5.  Ferric  oxide  +  hydrogen  = 

6.  Phosphorus  pentoxide  +  water  = 


70  REVIEW  QUESTIONS  AND  PROBLEMS 

36.  Write  the  equations  for  the  preparation  of  : 

1.  Carbon  dioxide  from  calcium  carbonate. 

2.  Ammonium  hydroxide  from  ammonium  chloride. 

3.  Chlorine  from  hydrochloric  acid. 

4.  Calcium  hydroxide  from  calcium  carbonate. 

5.  Nitric  acid  from  sodium  nitrate. 

37.  Complete,  using  formulas  : 

1.  Sodium  hydroxide  +  carbon  dioxide  = 

2.  Lead  nitrate  +  hydrogen  sulphide  = 

3.  Calcium  hydroxide  +  nitric  acid  = 

4.  Phosphorus  +  oxygen  = 

5.  Sodium  carbonate  +  calcium  chloride  = 

6.  Hydrogen  +  (hot)  copper  oxide  = 

State  which  of  the  above  compounds  are  acids,  bases, 
salts,  or  anhydrides. 

38.  Write  the  equations  for  the  preparation  of  («)  sulphur 
dioxide ;  (6)  hydrogen  sulphide ;  (V)  ammonia ;  ((f)  carbon 
dioxide;  (e)  nitric  acid. 

39.  Give  the  chemical  formulas  for  the  following :  dia- 
mond, carborundum,  black  lead,  marble,  sand  (pure),  washing 
soda,  lye,  blue  vitriol. 

40.  State  which  of  the  reactions  indicated  below  will  take 
place  in  aqueous  solution,  and  which  will  not,  and  give 
the  reasons  for  your  conclusion  in  each  case.    Complete  the 
equations,  using  formulas : 

1.  Barium  chloride  +  silver  nitrate  = 

2.  Calcium  chloride  +  carbon  dioxide  +  water  = 

3.  Copper  sulphate  +  zinc  = 

4.  Ferrous  sulphate  -f-  copper  = 

5.  Calcium  hydroxide  +  nitric  acid  = 

41.  Name  two  metals  which  have  a  valence  of  2  and  3 
respectively,  and  write  the  formulas  for  the  nitrates  and 
sulphates  of  these  metals. 


EQUATIONS  AND  GENERAL  FORMULAS    71 

42.  Give  the  chemical  names  and  formulas  for  the  follow- 
ing: baking  soda,  brimstone,   slaked  lime,  litharge,  quick- 
silver, oil  of  vitriol,  sal  ammoniac,  alum,  plaster  of  Paris, 
quartz,  niter. 

43.  Write  the  molecular  formulas  for  ozone,  sodium  sul- 
phate,  carbon    monoxide,    aluminum    chloride,    potassium 
hydroxide,    calcium    carbonate,    ferric    oxide,    phosphorus 
pentoxide,  lead  iodide,  phosphoric  acid. 

44.  Give  the  names  of  the  following  formulas  :  Hg  (NOg)2, 
CuO,  Ag2S04,  H202,  Br2,  Au,  H2S,  Pb(OH)2,  BaC08. 

45.  Write  the  formulas   for   nitrogen    peroxide,  carbon 
monoxide,  sulphuric  anhydride,  calcium  hydroxide,  cupric 
oxide,  stannic  chloride,  hydrogen  bromide,  potassium  car- 
bonate, silver  nitrate,  lead  sulphate. 

46.  Write  a  list  of  the  formulas  for  the  oxides  of  nitrogen, 
and  show  how  any  of  these  can  react  with  water.    Point  out 
how  any  two  of  this  series  of  compounds  illustrate  the  Law 
of  Multiple  Proportions. 

47.  Write  equations  showing  laboratory  methods  of  pre- 
paring  the    following :    (a)  hydrochloric  acid ;    (i)  sodium 
carbonate ;  (c)  ferric  hydroxide ;  (cf)  copper  sulphate. 

48.  Give  the  chemical  names  and  formulas  for  the  follow- 
ing: quicklime,  marble,  blue  vitriol,  bicarbonate  of  soda, 
litharge,  calomel.    If  any  reactions  are  possible  between 
these  substances  and  dilute  sulphuric  acid,  write  equations 
tor  show  them. 

49.  Write   equations    for   the  preparation   of   («)  CO2; 
(l>)  NaOH ;  (c)  H2S ;  (d)  AgCl ;  (e)  a  basic  oxide  and  HC1 ; 
(/)  an  acidic  oxide  and  KOH. 

50.  Describe  the  effects  observed  when  chlorine  water  is 
added  (a)  to  mercurous  chloride ;  (It)  to  potassium  iodide 
solution.    What  inference  do  you  draw  about  the  reactions 
that  have  taken  place  ? 


72  REVIEW  QUESTIONS  AND  PROBLEMS 

51.  Write  the  chemical  names  of  the  following:  H2SO3, 
NaHCO,,  H2S,  Fe2(SO4)8,  P2O5,  and  show  by  equation  how 
each  may  be  prepared. 

52.  Write  the  graphic  formula  for  (a)  nitric  acid ;  (b)  cal- 
cium carbonate  ;  (c)  acetic  acid. 

53.  Show  by  equation  the  bleaching  action  of  (a)  Cl ; 

(*)  so2. 

54.  Write  the  equations  for  the  preparation  of  the  follow- 
ing acids  other  than  by  the  direct  combination  of  the  elements 
involved :  H2S,  HN08,  H2S04,  HBr,  HC1,  H2C08,  H8P04. 

55.  Write  the  equations  for  the  following  reactions  : 

1.  Potassium  hydroxide  and  nitric  acid. 

2.  Ferrous  sulphide  and  hydrochloric  acid. 

3.  Barium  chloride  and  sodium  sulphate. 

4.  Calpium  hydroxide  and  ammonium  chloride. 

56.  Write  the  chemical  name  of  each  of  the  following : 
KHC08,  AsH8,  Ca8(P04)2,  C6H1206,  (C2H5)20. 

57.  Name   and   write   the  formulas   for   two  oxides    of 
phosphorus  and  the  acid  corresponding  to  each. 

58.  Write  the  formula  and  give  the  chemical  name  of 
saltpeter,  laughing  gas,  sugar  of  lead,  white  vitriol,  Glauber 
salts,  corrosive  sublimate,  plaster  of  Paris. 

59.  Describe  minutely,  giving  chemical  equations  to  show 
the  changes  which  take  place  : 

1.  When   strong   nitric    acid    reacts   with   metallic 

copper. 

2.  When  hydrogen  sulphide  is  passed  into  a  solution 

of  mercuric  chloride. 

3.  When  ammonium  sulphate  is  heated  with  a  solu- 

tion of  sodium  hydroxide. 

4.  When  bromine  water  and   sulphurous  acid  are 

mixed. 


EQUATIONS  AND  GENERAL  FORMULAS    73 

60.  («)  Complete,  using  formulas  : 

1.  Baric  nitrate  +  potassic  sulphate  = 

2.  Ammonic     chloride     (solid)  +  calcic     hydroxide 

(solid)  = 

3.  Sulphurous  oxide  •+-  oxygen  = 

(fi)  Give  equations  for  making  sulphuretted  hydrogen. 

61.  Write  the  formulas  for: 

1.  Three  chlorides  insoluble  in  water. 

2.  Four  sulphates  insoluble  in  water. 

3.  Two  sulphides  insoluble  in  water. 

4.  One  carbonate  soluble  in  water. 

62.  Name    the   following:   NaCIO,   NO,  KN02,  H2S08, 
FeCl8,  H8P04,  HP08,  CuaO,  CuBr2,  PbO2. 

63.  Write  the  equations  for  the  chemical  reactions  below : 

1.  Ammonium  chloride  and  slaked  lime. 

2.  Manganese  dioxide  and  hydrochloric  acid. 

3.  Nitric  acid  and  sodium  hydroxide. 

4.  Sodium  nitrate  and  sulphuric  acid. 

5.  Manganese  dioxide,  sodium  chloride,  and  sulphuric 

acid. 

64.  Write  equations  for  the  following  reactions : 

1.  Between  lead  peroxide  and  aqueous  hydrochloric 

acid. 

2.  On  subliming  mercuric  sulphate  and  aqueous  com- 

mon salt. 

3.  Between  aluminum  sulphate  and  aqueous  ammonia. 

4.  Between  aluminum  and  potassium  hydroxide. 

5.  Between  copper  sulphate  and  sodium  hydroxide. 

65.  Write  the  formula  for  phosphoric  acid,  acetic  acid, 
hydriodic  acid,  chromic  acid,  silicic  acid,  sulphurous  acid, 
nitrous  acid. 


74  REVIEW  QUESTIONS  AND  PROBLEMS  . 

CHAPTER  XXIII 

QUESTIONS  AND  CALCULATIONS 

A.   PERCENTAGE  COMPOSITION 

1.  Find  the  percentage  composition  of  carbon  in  («)  CH4; 
(ft)  C2H2;  (c)  C2H4;  (rZ)  COS;  («)  C4H10;  (/)  C6H10O5. 

2.  Calculate  the  percentage  composition  of  the  follow- 
ing compounds  :  carbon  dioxide,  ammonia,  ferric  oxide,  ace- 
tic acid,  calcium  sulphate,  cream  of  tartar,  ferrous  sulphate, 
alum. 

3.  How  much  sodium  in  (a)  10  g.  of  NaOH  ?  (ft)  19  g.  of 
Na2SO  4  ?  (e)  15  g.  of  NaCl  ?  (d)  22  g.  of  NaHS04  ? 

4.  Calculate  the  percentage  composition  of  (a)  galena; 
(7/)  pitchblende. 

5.  How  much  anhydrous  salt  in  («-)  a  kilogram  of  crys- 
talline Glauber  salts  ?  (b)  alum  ?  (e)  Epsom  salts  ?  (//)  sal 
soda  ?   (e)  copper  sulphate  ? 

6.  Find  the  percentage  of  the  elements  in  a  sample  of 
air  which  consists  of  12.37  g.  of  N  and  3.63  g.  of  O. 

7.  Calculate  the  percentage  composition  of  (a)  magnetic 
oxide  of   iron   (FegO4);   (&)  crystallized    sodium   carbonate 
(Na2CCylOH20). 

8.  How  many  grams  of  argon   can   be  obtained  from 
1500  kg.  of  normal  air  ? 

9.  Calculate  the  percentage   composition  of  («)   nitric 
acid ;  (b)  potassium  nitrate ;  (c)  sodium  nitrate. 

10.  Calculate  the  percentage  composition  of  («)  alcohol 
(C2H60);  (6)  acetic  acid  (C^O,);  (c)  cane  sugar  (CJH.OJ ; 
(d)  acetone  (CgH6O). 

11.  Find  the  percentage  composition  of  ether. 


QUESTIONS  AND  OAL(TLATrONS  75 

R   ATOMIC  AND  MOLECULAR  WEIGHTS 

1.  Suppose  10  g.  of  lead  yield  14.642  g.  of  lead  sulphate 
(PbS04).    Calculate  the  atomic  weights  of  S  on  the  assump- 
tion that  the  atomic  weights  of  lead  and  oxygen  are  206.91 
and  16  respectively. 

2.  A  certain  weight  of  copper  oxide,  when  heated  in  a 
current  of  H,  lost  59.789  g.  of  0  and  formed  67.282  g.  of 
water.    If  0  =  16,  what  is  the  atomic  weight  of  H  ? 

3.  One  gram  of  a  certain  metal  was  dissolved  in  HC1 
and  gave  1242  cc.  of  H  at  0°  C.  and  760  mm.    The  specific 
heat  was  found  to  be  23.    Calculate  the  equivalent  weight 
and  the  atomic  weight.    What  would  be  the  valence  of  the 
metal  ?  the  formula  of  the  chloride  ? 

4.  Suppose  13.67  g.  of  a  compound  of  lead  and  oxygen 
contained  12.39  g.  of  lead  and  1.28  g.  of  oxygen ;  what  is 
the  formula  of  the  compound  if  the  atomic  weight  of  lead 
is  206.9  ? 

5.  If  63.8351  g.  of  silver  iodide  yield  38.9656  g.  of  silver 
chloride,  what  is  the  atomic  weight  of  iodine  if  107.85  and 
35.46  are   accepted  as  the  atomic  weights  of  silver  and 
chlorine  respectively  ? 

6.  What  is  the  equivalent  of  Ni  if  it  dissolves  in  acids 
with  the  evolution  of  a  mass   of  H  equal  to  3.411  per 
cent  of  its  own  mass  ?    What  is  its  atomic  weight  if  it  is 
bivalent  ? 

7.  If  the  atomic  weight  of  Ag  is  197.94,  and  if  the  same 
electric  current,  on  passing  through  solutions  of  Ag  and 
Cu  salts,  precipitates  weights  of  the  metals  in  the  ratio  of 
l(Cu)  :  3.408  (Ag),  what  is  the  atomic  weight  of  copper  ? 

8.  The  specific  heat  of  P  is  0.189  and  its  vapor  density 
referred  to  hydrogen  is  62.    How  many  atoms  are  there  in 
a  molecule  of  phosphorus  gas  ? 


76  REVIEW  QUESTIONS  AND  PROBLEMS 

9.  Dumas  synthesized  silver  sulphide  (Ag.2S),  finding  the 
ratio  of  the  weights  of  silver  and  of  the  sulphide  to  be 
112.1943  : 128.8288.  The  atomic  weight  of  silver  is  107.94 ; 
find  the  atomic  weight  of  S. 

10.  A  chemist  converted  16.6450  g.  of  bismuth  oxide  in- 
to 25.2551  g.  of  bismuth  sulphate  (Bi2(S04)3).    The  atomic 
weight  of  S  is  32.06.    Calculate  that  of  bismuth. 

11.  Heinrichson  heated  31.20762  g.  of  calcite  and  obtained 
17.49526  g.  of  quicklime.    If  the  atomic  weights  of  oxygen 
and  carbon  are  16.00  and  12.001  respectively,  what  is  the 
atomic  weight  of  calcium  ? 

12.  A  chemist  obtained  from  59.4763  g.  of  magnesium 
sulphate  19.9379  g.  of  magnesia.    Calculate  from  this  data 
the  atomic  weight  of  Mg. 

13.  If  3.17  g.  of  iron  form  4.53  g.  of  Fe2O8,  what  is  the 
atomic  weight  of  iron  ? 

14.  If  200  parts  of  BaCl2  give  224.2  of  BaS04,  what  is 
the  atomic  weight  of  barium  ? 

15.  The  molecular  weight  of  lead  oxide  (PbO)  is  221.3. 
The  per  cent  of  lead  is  92.81.    Specific  heat  of  lead  is  0.031. 
What  is  its  atomic  weight  ? 

16.  The  specific  heat  of  Ag  is  0.056.    AVhat  is  its  atomic 
weight  ? 

17.  If  4.5  g.  of  Hg  unite  with  oxygen  to  form  4.86  g.  of 
mercuric  oxide,  and  the  specific  heat  of  mercury  is  0.032, 
what  is  its  atomic  weight  ? 

18.  A  metal  yields  a  chloride  containing  66.14  per  cent 
of  chlorine  and  having  the  specific  gravity  7.44.    What  is 
its  atomic  weight  ? 

19.  Dumas  found  that  2.399  g.  of  aluminum  chloride  re- 
quired 5.802  g.  of  silver  for  the  complete  precipitation  of 
the  chlorine.    Calculate  the  atomic  weight  of  aluminum. 


QUESTIONS  AND  CALCULATIONS  77 

Calculate  the  molecular  weights  of  the  following : 

20.  NH4C1;  (NH4)2C08;  NH4HC08;  (NH4)2Cr04;  NH4CN; 
NH4F;  (NH4)2Mg04;  NH4NO8;  NH4NO2; 

21.  CaC08;  CaAl204;  Ca(HC08)2;  CaO;  Ca^lO^;  CaF2; 
Ca(OH)2;  CaI2;  CaS04;  C02; 

22.  FeAs04.2H20;  FeClg;  FeC08;  Fe804;  FeS; 

23.  Pb(C2H802)2;    Pb(B02)2.H20;    PbBr2;    Pb(N08)2; 
PbO;  Pb304; 

24.  MgF2;    MgS04.7H2O;    MnCl2;  Mn(OH)2;    HgCl2; 
HgS04; 

25.  NiAs;  NiCC^O,),;  NiC08;  HN08;  N2;  N2O;  NOC1; 

26.  Sn02;  Sn2Fe(CN)6;   SnF2;   SrBr2;  SrC2; 
H20;  H2S04;  SOBr2;  TaBr5; 

27.  Mn208-H20;  (CaBa)C08;  CaC08(MgFe)C08; 
(K2Ba)  A^Sip^ ;  (NaK)  AlSig08. 

C.    SIMPLEST  FORMULAS 

1.  Calculate  the  simplest  formula  for  the  compounds  hav- 
ing the  percentage  composition  (a)  N  =  82.35,  H  =  17.64 ; 
(b)  N  =  26.17,  Cl  =  66.35,  H  =  7.48. 

2.  Calculate  the  simplest  formula  for  the  substances  hav- 
ing the  composition  (a)  0  =  76.19,  H  =  1.58,  N  =  22.22 ; 
(/>)  N  =  13.86,  K  =  38.61,  0  =  47.52. 

3.  Find  the  simplest  formulas  for  the  substances  hav- 
ing the  following  composition :  (a)  H  =  1.58,  N  =  22.22, 
0  =  76.19 ;  (i)  0  =  47.53,  N  =  13.86,  K  =  38.61. 

4.  Calculate  the  simplest  formula  for  the  compounds  hav- 
ing the  percentage  composition  :  (a)  N  =  82.353,  H  =  17.647 ; 
(b)  0  =  30,  Fe  =  70  ;  (c)  H  =  1,  C  =  12,  K  =  39,  O  =  48. 

5.  What  is  the  simplest  formula  for  a  compound  having 
the  composition  H  =  7.69  and  C  =  92.3  ? 


78  REVIEW  QUESTIONS  AND  PROBLEMS 

6.  Calculate  the  simplest  formulas  for  the  substances 
having  the  composition  (a)  C  =  40,  H  =  6.67,  0  =  53.33 ; 
(ft)  C  =  16.8,  H  =  5.26,  N  =  36.84,  S  =  42.1 ;  (c)  C  =  54.55, 
H  =  9.09,  0  =  36.36. 

7.  Calculate  the  formulas  for  the  following : 

Cu  =  34.46.    CaO  =  43.45.      Ag  =  53.15.     Lithia=6.43. 
Fe  =  30.59.     A1208  =  17.68.    Cu  =  31.08.     Alumina  =  29.26. 
8  =  34.95.       Si02  =  38.87.      8  =  15.77.        Silica  =64.31. 

8.  What  is  the  simplest  formula  for  a  mineral  whose 
percentage  composition  is  as  follows:   Ca,  50.12  per  cent; 
C,  12.04  per  cent ;  and  0,  47.84  per  cent. 

9.  A  liter  of  gas  weighs  1.16  g.   Is  its  formula  CH,  C2H2, 
orC4H4? 

10.  The  analysis  of  a  certain  compound  gave  the  follow- 
ing results : 

1.  C  =12.00  2.  11.69  3.  11.83 

H  =    3.98  4.02  4.00 

N  =    6.77  6.80  6.78 

Br  =  77.56  77.61  77.64 

What  is  its  formula  ? 

D.    MOLECULAR  FOKMULAS 

1.  The  vapor  density  of  steam  is  9.   The  percentage 
composition  of  water  is  H  =  11.11,  0  =  88.89.    What  is 
the  formula  of  steam  ? 

2.  Find  the  formula  for  a  hydrocarbon  that  contains  an 
equal  number  of  hydrogen  and  carbon  atoms,  and  the  vapor 
of  which  has  a  density  (air)  of  2. 

3.  If  750  cc.  of  CO  weighs  0.94  g.,  what  is  the  molecular 
weight  of  the  compound  ? 


ni  KS'I 'IONS  AND  CALCULATIONS  79 

4.  Calculate  the  formulas  for  the  compounds  having  the 
following  percentage  composition  and  vapor  density  : 

1.  C  =  92.3  per  cent,  H  =  7.7  per  cent,  vapor  den- 

sity ==  39. 

2.  C  =  73.8  per  cent,  H  =  8.7  per  cent,  N  =  17.5  per 

cent,  vapor  density  =  80.2. 

3.  C  =  39.9  per  cent,  H  =  6.7  per  cent,  O  =  53.4  per 

cent,  vapor  density  =  30.5. 

4.  C  =  10.04  per  cent,  H  =  0.84  per  cent,  Cl  =  89.12 

per  cent,  vapor  density  =  59.7. 

5.  The  vapor  density  of  Cl  is  35.45.  What  is  its  molecular 
weight  ? 

6.  What  is  the  formula  for  mercuric  chloride  as  deduced 
from  the  following  data :  weight  of  flask  full  of  vapor  at 
350°  and  758.4  mm.  =  27.401  g ;  capacity  of  flask  =  250  cc.  ? 

7.  The  specific  heat  of  P  is,  0.189  and  its  vapor  density 
referred  to  H  is  62.    How  many  atoms  are  there  in  a  mole- 
cule of  phosphorus  gas? 

8.  The  gas  density  of  sodium  vapor  is  11.5.    Calculate 
the  number  of  atoms  in  a  molecule  of  sodium  vapor. 

9.  A  gaseous  compound  of  H  and  C  is  found  to  contain 
12  parts  by  weight  of  carbon  to  1  part  of  hydrogen.    Its 
gas  density  is  13.    What  is  its  formula  ? 

10.  If  1500  cc.  of  CO  gas  weigh  1.8816  g.,  what  is  the 
molecular  weight  of  the  compound  ? 

11.  Calculate  the  molecular  formulas  for  the  compounds 
corresponding  to  the  following  data : 

1.  C  =  73.8,  H  =  8.7,  N  =  17.1,  vapor  density  =  5.03. 

2.  C  =  92.3,  H  =  7.7,  vapor  density  =  2.425. 

3.  C  =  39.9,  H  =  0.7, 0  =  53.4,  vapor  density  =  1.906. 

Yapm-  density  in  rach  case  is  referred  to  oxygen. 


80  REVIEW  QUESTIONS  AND  PROBLEMS 

12.  An  oxide  of  carbon  contains  42.85  per  cent  of  carbon. 
Calculate  the  molecular  formula  if  a  liter  of  the  gas  weighs 
1.25  g.  under  standard  conditions. 

13.  A  volatile  liquid  contains  37.5  per  cent  of   carbon, 
50  per  cent  of  oxygen,  and  12.5  per  cent  of  hydrogen.  A  liter 
of  the  vapor  weighs  about  16  times  that  of  hydrogen.    What 
is  the  molecular  formula  ? 

14.  If  a  hydrocarbon  contains  80  per  cent  carbon  and  a 
liter  of  it  weighs  1.346  g.,  what  is  its  formula  ? 

15.  Employ   Avogadro's    hypothesis    in   calculating   the 
atomic  weight  of  oxygen  from  the  following  data :  carbonic 
acid  gas,  steam,  laughing  gas,  and  sulphurous  anhydride  con- 
tain in  the  order  named  72.73,  88.89,  36.364,  and  50.00  per 
cent  by  weight  of  oxygen ;  and  their  densities  referred  to 
H  are,  in  the  same  order,  22,  9,  22,  and  32. 

16.  A  gas  has  the  formula  C3Hg.    Is  it  lighter  or  heavier 
than  air  ? 

17.  A  liter  of  arsine  weighs  3.49  g.  under  standard  condi- 
tions ;  find  its  molecular  weight. 

18.  What  is  the  molecular  weight  of  marsh  gas,  3  1.  of 
which  weigh  2.15  g.? 

19.  Calculate  the  molecular  weights  of  the  following  gases 
from  their  vapor  densities :  (a)  chlorine,  35.5 ;  (7>)  hydro- 
chloric acid,   18.25 ;    (c)  ammonia,   8.5 ;   (<7)   nitrogen,   1'4 ; 
(e)  steam,  9. 

20.  Sulphur  dioxide  is  2.22  times  as  heavy  as  air ;   find 
its  density  and  the  molecular  weight. 

21.  The  specific  gravity  of  ammonia  compared  to  hydro- 
,  gen  is  8.5.    What  is  its  molecular  weight  ?    Explain  the 

steps  by  which  it  is  obtained. 

22.  At  what  temperature  does  air  have  the  density  of 
H  at  0°C.? 


WEIGHTS  AND  VOLUMES  FROM  EQUATIONS       81 

CHAPTER  XXIV 
WEIGHTS  AND  VOLUMES  FROM  EQUATIONS 

1.  What  weight  of  hydrogen  will  be  required  for  the  com- 
plete reduction  of  10  g.  of  CuO  ?    What  will  be  the  volume 
at  a  temperature  of  15°  C.  and  740  mm.  pressure  ? 

2.  What  weight  of  potassium  chlorate  (KC108)  would  be 
needed  to  generate  sufficient  oxygen  to  fill  a  cylinder  of 
50  1.  capacity  under  a  pressure  of  1000  cm.  of  mercury  and 
a  temperature  of  15°  C.  ? 

3.  The  capacity  of  a  balloon  is  10,000  cu.  ft.    How  much 
would  it  cost  to  fill  it  with  hydrogen  at  a  pressure  of  800  mm. 
and  at  a  temperature  of  23°  C.,  the  H  being  made  from  Zn 
costing  20  ct.  per  pound  and  sulphuric  acid  costing  8  ct. 
per  pound? 

4.  What  weight  of  ammonium  chloride  will  yield  1 1.  of  am- 
monia at  a  pressure  of  740  mm.  and  a  temperature  of  22°  C.  ? 

5.  What  would  be  the  volume  under  standard  conditions 
of  a  quantity  of  air  that  occupies  200  cc.  at  20°  C.  under  a 
pressure  of  740  mm.  of  mercury  ? 

6.  How  many  liters  of  nitrogen  monoxide  can  be  prepared 
from  100  g.  of  ammonium  nitrate  ? 

'7.  What  volume  of  a  solution  of  H2S04  that  contains 
40  g.  of  H2S04  in  one  liter  will  be  required  for  the  exact 
neutralization  of  10  cc.  of  a  solution  of  NaOH  containing 
20  g.  of  NaOH  to  one  liter  ? 

8.  What  volume  of  ammonia  gas,  temperature  20°  C.,  pres- 
sure 740  mm.,  can  be  obtained  from  214  g.  of  sal  ammoniac, 
and  how  should  one  proceed  to  prepare  it  ? 

9.  How  much  sodic  chloride  may  te  formed  from  10  g. 
of  crystallized  sodic  carbonate  (NaaCO,  •  10  H/))  ? 


82  REVIEW  QUESTIONS  AND  PROBLEMS 

10.  How  much  CO2  by  weight  and  by  volume  can  be  ob- 
tained from  53  g.  of  sodium  carbonate  ?   What  volume  would 
the  gas  occupy  at  20°  C.  and  750  mm.  pressure  ? 

11.  Calculate  the  volume  of  C02  at  0°C.  and  760mm. 
that  can  be  made  from  50  g.  of  calcium  carbonate  and  an 
excess  of  HC1. 

12.  What  volume  will  25  kg.  of  oxygen  occupy  at  a  tem- 
perature of  18°  C.  and  a  pressure  of  740  mm.? 

13.  What  weight  of  sulphur  is  necessary  to  produce  100  1. 
of  SO2  at  a  temperature  of  20°  C.  and  a  pressure  of  two 
atmospheres  ? 

14.  How  many  cubic  centimeters  of  H2SO4,  containing 
49  g.  of  H2S04  per  liter,  will  be  required  to  neutralize  2  g. 
of  NaOH  ? 

15.  Find  the  number  of  grams  of  H2S04  required  to  unite 
with  176  g.  of  iron  sulphide  to  form  H2S. 

16.  How  many  liters  of  oxygen  at  standard  conditions 
would  be  formed  by  the  complete  decomposition  of  25  g.  of 
mercuric  oxide  ? 

17.  How  many  tons  of  oil  of  vitriol  containing  70  per  cent 
H2SO4  are  needed  to  convert  100  t.  of  salt  into  salt  cake? 

18.  How   much    sulphuric   acid   and    potassium    nitrate 
would  be  required  to  prepare  100  g.  of  HN08? 

19.  Compute  the  weight  of  KOH  required  for  the  exact 
neutralization  of  the  total  quantity  of  HC1  obtained  from 
175.5  g.  of  NaOH  by  the  action  of  H2S04. 

20.  A  solution  of  5  g.  of  potassium  iodide  is  precipitated 
with  silver  nitrate.    W'hat  will  be  the  weight  of  the  precipi- 
tate of  silver  iodide  ? 

21.  If  sodium  nitrate,  ammonium  nitrate,  and  potassium 
nitrate  were  the  same  price  per  pound,  which  would  be 
cheapest  to  use  for  preparing  nitric  acid,  and  why  ? 


WEIGHTS  AND  VOLUMES  FROM  EQUATIONS       83 

22.  What  relative  weights  of  cupric  oxide  and  cuprous 
oxide  are  procurable  from  the  same  weight  of  copper  ? 

23.  Compare  the  weights  of  aluminum  and  zinc  necessary 
for  the  production  of  equal  weights  of  hydrogen  by  the 
interaction  with  an  acid. 

24.  What  weight  of  H2S04  can  be  prepared  from  100  g. 
of  sulphur  ? 

25.  What  weight  of  potassium  bromate  can  be  obtained 
by  neutralizing  1520  g.  of  bromine  with  potash  ? 

26.  What  weight  of  limestone  is  needed  to  convert  90  tons 
of  soda  crystals  into  sodium  bicarbonate  ? 

27.  How  many  grams  of  CO2  will  combine  with  100  g.  of 
CaO  to  form  CaCO8? 

28.  How  much  CaSO4  can  be  formed  from  37  g.  of  CaCl2? 

29.  What  weight  of  Al2Og  will  be  needed  to  prepare  94.8  g. 
of  potash  alum  ? 

30.  What  weight  of  sodium  carbonate  can  be  made  from 
500  kg.  of  common  salt  ? 

31.  Assume  that  thermit  contains  75  per  cent  iron  oxide ; 
how  much  of  the  mixture  would  be  required  to  produce  6  Ib. 
of  metallic  iron  ? 

32.  Find  the  oxygen  necessary  to  burn  100  g.  of  CS2. 

33.  How  many  grams  of  iron  sulphide  are  necessary  to 
prepare  100 1.  of  hydrosulphuric  acid  when  the  laboratory 
conditions  are  17°  C.  and  the  pressure  740  mm.  ? 

34.  What  weight  of  sodium  chloride  is  necessary  to  pre- 
pare sufficient  hydrochloric  acid  to  saturate  1 1.  of  water 
under  standard  conditions  ? 

35.  On  the  supposition  that  calcium  carbide  costs  12  ct. 
a  kilogram,  what  would  be  the  cost  of  an  amount  suffi- 
cient to  generate  100 1.  of  acetylene  measured  at  20°  C.  and 
TlOiiiiu.? 


84  REVIEW  QUESTIONS  AND  PROBLEMS 

36.  What  weight  of  sodium  carbonate  crystals  will  1  kg. 
of  the  anhydrous  salt  yield  ? 

37.  Write  the  equations  for  the  preparation  of  3  kg.  of 
KOH  by  three  different  methods. 

38.  Supposing  bauxite  to  be  aluminum  hydroxide,  what 
weight  of  it  is  necessary  for  the  prepai-ation  of  100  kg. 
of  Al? 

39.  How  much  water  is  necessary  to  convert  50  g.  of 
P205  into  hydrogen  phosphite  ? 

40.  How  much  carbon  would  be  necessary  to  convert  50  g. 
of  CuO  into  pure  copper  ? 

41.  How  much  nitric  and  sulphuric  acid  is  needed  to  pre- 
pare nitric  acid  enough  to  exactly  neutralize  5  Ib.  of  chalk  ? 

42.  How  many  tons  of  coke  containing  97  per  cent  carbon 
are  required  to  reduce  388  t.  of  hematite  ? 

43.  In  burning  27  g.  of  alcohol  find  the  weight  of  the 
products. 

44.  What  weight  of  Cl  can  be  prepared  from  78  g.  of  rock 
salt  containing  99  per  cent  NaCI  ?    How  much  Mn02  and 
H2S04  would  be  required  to  carry  out  the  reaction  ?    What 
volume  would  the  Cl  occupy  under  standard  conditions,  and 
what  volume  of  HC1  would  be  formed  ? 

45.  How  much  metallic  iron  can  be  made  by  reducing 
230  g.  of  ferric  oxide  ? 

46.  Calculate  the  volume  of  a  solution  of  H2S04,  den- 
sity 1.8  and  containing  89  per  cent  pure  acid,  that  would 
be  required  to  make  200  g.  of  HC1  by  acting  on  sodium 
chloride. 

47.  What   weight   of  ammonium   chloride,  when   acted 
upon  by  calcium  hydroxide,  is  required  to  produce  17  g.  of 
ammonia  gas,  and  what  weight  of  calcium  chloride  is  formed 
at  the  same  time  ? 


MISCELLANEOUS  QUESTIONS  AND  PROBLEMS      85 

48.  To  neutralize  completely  196  g.  of  H^SO^  what  weight 
of  crystallized  sodium  carbonate  (Na2C08  •  10  H20)  is  re- 
quired ?  The  volume  of  C02  evolved  is  approximately  4450 cc. 
under  standard  conditions.   Calculate  its  volume  at  890  mm. 
pressure  and  27°  C. 

49.  What  volume  of  nitrous  oxide  (N20)  measured  at 
0°  C.  and  750  mm.  would  be  evolved  by  the  decomposition 
of  10  g.  of  ammonium  nitrate,  assuming  the  weight  of  1 1.  of 
nitrous  oxide  at  0°  C.  and  760  mm.  to  be  1.97  g.  ? 


CHAPTER  XXV 
MISCELLANEOUS  QUESTIONS  AND  PROBLEMS 

1.  Mention  the  constituents  of  water  and   give  their 
properties  by  volume  and  by  weight.    Compare  them  as  to 
physical  and  chemical  properties. 

2.  State  and  illustrate  the  Law  of  Multiple  Proportions. 

3.  Find   the   percentage  composition   of   H2S04.    How 
many  grains  of  SO2  can  be  set  free  by  the  action  of  325  g. 
of  the  acid  on  copper  ? 

4.  Describe  the  usual  methods  of  preparing  ammonia  on 
a  commercial  scale.    Write  the  equation. 

5.  Describe  an  experiment   illustrating   the   bleaching 
properties  of  S02.    Explain. 

6.  Distinguish  between  («)  allotropism  and  isomerism; 
(ft)  efflorescence  and  deliquescence ;  (c)  hard  and  soft  water. 

7.  Mention  three  distinct  allotropic  forms  of  carbon. 
Compare  the  physical  properties  of  the  forms  mentioned. 

8.  Describe  a  method  of  manufacturing  matches.    Write 
two  reactions  that  take  place  when  a  common  friction  match 
is  ignited. 


86  REVIEW  QUESTIONS  AND  PROBLEMS 

9.  Distinguish  between  (a)  a  physical  change  and  a 
chemical  change ;  (&)  between  a  mixture  and  a  chemical 
compound;  (c)  illustrate  each. 

10.  Mention  the  constituent  metals  of  these  alloys :  bell 
metal,  pewter,  brass,  soft  solder,  German  silver,  type  metal, 
Babbitt  metal. 

11.  Write  the  chemical  name  of  each:  white  lead,  blue 
vitriol,  calomel,  gypsum,  caustic  potash,  copperas. 

12.  Describe  a  method  of  preparing  phosphorus  and  write 
the  reactions.  % 

13.  Find  the  weight  of  the  products  of  combustion  when 
26  g.  of  alcohol  (C2H60)  are  burned. 

14.  Write  the  graphic  formula  of  hydrogen  arsenide  and 
the  reaction  for  its  complete  combustion. 

15.  Describe  an  experiment  to  show  that  a  metal  changes 
in  weight  when  heated  in  air.    Explain. 

16.  What  is  a  solution  ?   Describe  an  experiment  to  illus- 
trate (a)  a  saturated  solution  ;  (A)  a  supersaturated  solution. 

17.  Describe  a  method  of  preparing  nitrogen  and  make  a 
sketch  of  the  apparatus.    Give  the  important  physical  and 
chemical  properties  of  N. 

18.  Give  the  important  physical  and  chemical  properties 
of  bromine.  Mention  one  source  and  two  uses  of  bromine. 

19.  Describe  a  test  to  show  the  presence  of  each  of  the 
following :  oxygen,  iodine,  sodium,  carbon  dioxide,  lead. 

20.  A   liter  of   gas   under   standard   conditions   weighs 
2.0608  g.    Find   (a)   its  vapor  density ;    (7>)  its  molecular 
weight. 

21.  Name  four  important  constituents  of  the  air  and  give 
the  relation  of  each  to  plant  and  animal  life. 

22.  Describe  the  preparation  of  nitrous  oxide,  writing 
the  reaction,  and  give  the  important  properties. 


MISCELLANEOUS  QUESTIONS  AND  PROBLEMS      87 

23.  Describe  the  process  by  which  the  pig  iron  of  com- 
merce is  obtained  from  the  ore  by  means  of  a  blast  furnace. 

24.  Name  the  four  most  important  constituents  of  ordinary 
illuminating  gas.     Give  the  relative  importance  of  these 
constituents  in  the  production  of  (a)  light;  (6)  heat. 

25.  Describe  the  Bessemer  process  of  manufacturing  steel 
and  make  a  tabular  statement  of  the  physical  and  chemical 
difference  between  wrought  iron  and  cast  iron. 

26.  What  substance  did  you  employ  in  the  laboratory 
preparation  of  hydrochloric  acid  ?   Why  was  each  substance 
selected  ? 

27.  Describe  the  action  and  explain  what  occurs  when 
chlorine  water  is  added  to  a  solution  of  potassium  iodide 
containing  starch. 

28.  Give  three  methods  for  collecting  gases  and  state 
the  conditions  under  which  each  may  be  advantageously 
employed. 

29.  How  many  cubic  centimeters  of  H2SO4,  containing 
49  g.  per  liter,  will  be  required  to  neutralize  2  g.  of  sodium 
hydroxide  ? 

30.  Describe  the  preparation  of  hydrogen  gas  and  make 
a  sketch  of  the  apparatus  used.    How  can  it  be  proved  ex- 
perimentally that  water  is  formed  when  H  burns  ? 

31.  («)  How  is  coal  gas  manufactured  ?    (£)  How  could 
you  show  by  experiment  that  particles  of  solid  carbon  are 
present  in  a  luminous  flame  of  coal  gas  ?    (c)  Why  is  a 
Bunsen  flame  nonluminous  ? 

32.  Describe  the  process  by  which  metallic  aluminum  is 
manufactured.    Describe  the  reaction  that  takes  place  be- 
tween metallic  aluminum  and  ferric  oxide  when  a  mixture 
of  the  two  is  ignited.    What  practical  applications  are  made 
of  this  reaction  ? 


88  REVIEW  QUESTIONS  AND  PROBLEMS 

33.  What  is  meant  by  the  term  "  catalysis  "  ?    tfame  three 
processes  or  reactions  where  a  catalytic  agent  is  present. 

34.  Describe  the  essential  features  of  the  mechanical  fil- 
tration process  for  the  purification  of  large  water  supplies. 

35.  What  occurs  when  a  solution  of  copper  sulphate  is 
electrolyzed  (a)  with  both  electrodes  of  platinum  ?  (i)  with 
both  electrodes  of  copper?   Describe  the  electrolytic  puri- 
fication of  crude  copper. 

36.  Define  basic  anhydride  and  acid  anhydride;  give  an 
example  of  each.    What  is  a  dibasic  acid  ?   Give  examples. 

37.  Describe    in   detail   the   Le   Blanc   process    for   the 
manufacture  of  soda. 

38.  Discuss  the  periodic  classification  of  the  elements. 

39.  Explain  briefly  two  practical  methods  of  determining 
the  combining  weights  of  oxygen  and  hydrogen. 

40.  How  may  lime  be  shown  to  be  the  oxide  of  a  metal  ? 

41.  How  may  sulphuretted   hydrogen  be  made?    Give 
the  properties  and  uses  of  this  substance. 

42.  What   is   soap  ?    How   is    it   made  ?    What   is   the 
difference  between  hard  soap  and  soft  soap  ? 

43.  Name  three  substances  occurring  in  nature  that  are 
composed  of  calcium  carbonate.  What  substances  are  formed 
when  calcium  carbonate  is  highly  heated  ?    What  change 
takes  place  when  water  is  added  to  the  solid  product  thus 
formed  ?  What  use  is  made  of  the  latter  substance  ?   What 
chemical  change  occurs  when  it  is  exposed  to  the  air  ? 

44.  What  is  plaster  of  Paris  ?    What  chemical  difference 
is  there  between  the  hardening  of  mortar  and  the  setting 
of  plaster  of  Paris  ? 

45.  State  by  what  experiments  you  could  find  out  whether 
or  not  a  compound  (a)  contains  water  of  crystallization; 
(i)  is  efflorescent ;  (c)  gives  ions  in  dissolving ;  (d)  is  an  acid. 


MISCELLANEOUS  QUESTIONS  AND  PROBLEMS      80 

46.  What  experiments  should  you  make  to  distinguish 
between   (a)   magnesium   oxide    and   flour?    (7>)  potassium 
chloride  and  potassium  bromide  ? 

47.  State  the  practical  use  and  explain  the  efficiency  of 
the  Davy  safety  lamp. 

48.  Mention  the  chemical  name  and  write  the  formula  of 
each  of  two  oxides  of  phosphorus,  and  describe  a  method 
of  preparing  each. 

49.  Define  kindling  temperature.   Mention,  in  the  order  of 
their  kindling  points,  charcoal,  sulphur,  coal,  phosphorus. 

50.  Describe,  writing  the  reactions,  a  method  of  preparing 
ammonia  by  the  action  of  an  alkali  on  an  ammonium  salt. 

51.  Define  and  illustrate  filtrate,  reagent,  triad,  halogen, 
positive  element,  hydroxide,  isomerism. 

52.  Distinguish  in  meaning  between  the  following  suffixes 
when  used  in  names  of  chemical  compounds :   (a)  ous  and 
ic :  (£»)  ite  and  ate ;  (c)  and  the  prefixes  hyjjo  and  per. 

53.  Find  under  standard  conditions  the  weight  of  1 1. 
of  CO. 

54.  Define  fermentation.    Describe  a  laboratory  experi- 
ment to  illustrate  fermentation,  writing  the  reactions. 

55.  Describe  the  occurrence  of  S  in  nature.    Describe  the 
process  of  extracting  sulphur  from  one  of  its  ores. 

56.  Describe  the  manufacture  of  safety  matches  and  state 
why  they  are  safer  than  other  matches.   Write  the  chemical 
reactions  that  occur  when  safety  matches  are  ignited. 

57.  Describe  the  process  of  extracting  mercury  from  one 
of  its  ores,  writing  the  reaction.     Mention  the  important 
physical  properties  and  the  principal  uses  of  mercury. 

58.  In  what  compound  does   chlorine  usually  occur  in 
nature  (give  chemical  and  common  name)?    Show  by  equa- 
tion how  free  chlorine  is  obtained  from  this  body. 


90  REVIEW  QUESTIONS  AND  PROBLEMS 

59.  How  is  sulphur  dioxide  made  from  sulphur  and  how 
is  sulphuric  acid  made  from  it  ?    Write  equations. 

60.  Show  by  equations  how  calcium  carbonate  decom- 
poses on  heating  and  how  it  reacts  with  dilute  H2SO4.    Give 
the  common  names  of  the  products  of  both  reactions. 

61.  Point  out  the  chemical  similarity  between  chlorine, 
bromine,  and  iodine.    What  is  this  group  called  ?    How  is 
each  of  these  elements  set  free  from  a  salt  containing  it  ? 

62.  Give  the  Laws  of  Definite  and  Multiple  Proportion 
and  point  out  what  relation  they  have  to  the  atomic  theory. 

63.  What  is  the  basis  of  the  Mendeleeff  classification  ? 
What  evidence  have  we  that  this  is  a  natural  classification  ? 
Discuss  the  properties  of  the  elements  in  some  natural  family 
in  such  a  way  as  to  show  their  apparent  relation. 

64.  Define  the  terms  "  atom,"  "  valence,"  "  equivalent," 
and  "  gram-molecule."  Explain  the  following  processes :  dis- 
tillation, sublimation,  electrolysis,  neutralization,  reduction, 
fermentation,  precipitation  ? 

65.  To  what  constituents  do  acids  owe  their  characteris- 
tic properties  ?   Does  this  substance  impart  these  proper- 
ties to  all  its  compounds  ?   What  is  the  theory  advanced  to 
explain  the  facts  embraced  in  your  answer?    How  do  we 
explain  the  fact  that  some  acids  are  stronger  than  others  ? 
Name  some  other  facts  which  the  above-mentioned  theory 
explains. 

66.  One  volume  of  oxygen  at  100°  C.  will  go  to  form  how 
many  volumes  of  steam  under  the  same  conditions  ?    How 
will  the  number  of  molecules  of  each  compare  ?  What  in- 
ference can  be  drawn  from  the  last  answer  as  to  the  char- 
acter of  the  oxygen  molecule  ?    How  do  we  account  for 
the  increase  in  the  density  when  oxygen  is  converted  into 
ozone  ? 


MISCELLANEOUS  QUESTIONS  AND  PROBLEMS      91 

67.  Give  an  account  of  the  manufacture  of  H2S04.  Write 
the  equations.    How  are  the  pan  acid  and  concentrated  acid 
obtained  from  the  chamber  acid?    Give  the  uses  to  which 
this  acid  is  put. 

68.  Define  the  terms  "  acid,"  "  base,"  and  "  salt."  Discuss 
the  process  of  neutralization.    What  is  the  modern  concep- 
tion as  to  the  condition  of  acids,  bases,  and  salts  in  dilute 
aqueous  solutions  ? 

69.  Describe  the  Solway  process  for  the  manufacture  of 
soda,  giving  the  reactions. 

70.  State  the  Law  of  Gay-Lussac  and  the  hypothesis  of 
Avogadro,  and  illustrate  each. 

71.  Give  the  principal  sources  and  the  chemical  and  phys- 
ical properties  of  the  following  elements  :  hydrogen,  sulphur, 
nitrogen,  carbon,  sodium,  and  zinc. 

72.  How  much  metallic  iron  can  be  obtained  by  reducing 
23  g.  of  ferric  oxide  ? 

73.  If  a  quantity  of  steam  which,  at  100°  C.  and  standard 
pressure,  occupies  500  cc.  be  cooled  to  4°  C.,  what  will  be 
the  volume  of  its  resulting  water  ?   What  will  it  weigh  ? 

74.  Give  the  properties   of  sodium,  potassium,  copper, 
lead,  and  phosphorus,  and  the  equations  for  the  preparation 
of  each. 

75.  Describe  the  manufacture  of  white  lead,  the  making 
of  caustic  soda,  or  the  refining  of  copper. 

76.  Are  the  reactions  reversible  by  which  («)  oxygen 
is  obtained  from  potassium  chlorate  ?   (i)  ^hydrogen  from 
sodium  and  water  ?    (c)  water  from  oxygen  and  hydrogen  ? 
Why? 

77.  When  dilute  acid  is  poured  on  zinc,  what  causes  the 
reaction  to  go  in  one  direction  only  ?    If  H  dissolved  abun- 
dantly in  water,  how  far  would  the  reaction  go  ? 


92  REVIEW  QUESTIONS  AND  PROBLEMS 

78.  Is  the  burning  of  a  candle  a  reversible  reaction  that 
runs  to  equilibrium  ?    Why  ? 

79.  Thin  layers  of  oxides  form  over  the  surfaces  of  most 
metals,  making  soldering  impossible.    The  tinsmith  makes 
firm  joints  by  using  acid  or  rosin  when  soldering.    Explain 
the  action. 

80.  Experiments  show  that  13.1  g.  of  zinc  unite  with  32  g. 
of  oxygen  to  form  zinc  oxide.     Calculate  the  combining 
weight  of  zinc. 

81.  Name  the  following  compounds  and  write  the  formulas: 

1.  The  magnesium  salt  of  chloric  acid. 

2.  The  zinc  salt  of  chlorous  acid. 

3.  The  calcium  salt  of  nitrous  acid. 

4.  The  potassium  salt  of  hypochlorous  acid. 

5.  The  sodium  salt  of  carbonic  acid. 

6.  The  lithium  salt  of  perchloric  acid. 

7.  The  mercurous  salt  of  nitric  acid. 

8.  The  mercurous  salt  of  nitrous  acid. 

9.  The  mercuric  salt  of  nitric  acid. 

10.  The  compound  of  sodium  and  hydrogen. 

11.  The  compound  of  aluminum  and  silicon. 

12.  The  two  compounds  of  tin  and  sulphur. 

82.  1  g.  of  aluminum  acted  on  by  acid  yields  1230  cc.  of 
H  under  standard  conditions.    Calculate  the  apparent  com- 
bining weight  of  Al,  and  correct  this  by  the  use  of  Dulong 
and  Petit's  Law,  the  specific  heat  of  Al  being  0.22. 

83.  What  is  a  flame  ?   What  causes  the  luminosity  of  a 
flame  ?    Why  is  the  Bunsen  flame  nonluminous  ?    Describe 
the  structure  of  the  Bunsen  flame. 

84.  State    Avogadro's    hypothesis    and    illustrate    it   by 
means  of  the  union  of  H  and  0  to  form  water,  and  of  Cl 
and  H  to  form  HC1. 


MISCELLANEOUS  QUESTIONS  AND  PROBLEMS      93 

85.  A  solution  of  potassium  permanganate  undergoes  no 
change  when  a  current  of  hydrogen  gas  is  caused  to  bubble 
through  it.    It  is  soon  decolorized,  however,  after  treatment 
with  zinc  and  sulphuric  acid.    Explain  fully  the  principle 
underlying  these  facts. 

86.  What  is  ozone?  How  may  it  be  prepared?  What  are 
its  properties  ?   What  is  hydrogen  peroxide  ?    What  are  its 
properties  ? 

87.  What  advances  of  practical  importance  have  resulted 
from  the  study  of  chemistry  and  from  chemical  investigation  ? 

88.  How  is  ammonia  used  in  refrigeration  ?   How  do  you 
class  the  radical  NH4  ? 

89.  Give  the  formula  and  properties  of  acetylene  and 
describe  a  method  by  which  it  may  be  made. 

90.  The  atomic  weight  of  carbon  is  12  and  of  oxygen 
15.9.    What  is  the  weight  of  1 1.  of  a  gas  of  the  formula 
<  J  1 ,.  <  M ),.  <  '< ),  C2H2 ?  What  volume  of  0  will  be  necessary 
for  the  complete  combustion  of  1 1.  of  each  of  these  gases  ? 
Give  equation  in  each  case. 

91.  Give  the  equations  illustrating  the  formation  of  HaSO4 
from  sulphur  dioxide,  air,  steam,  and  the  oxides  of  nitrogen. 
State  the  properties  of  concentrated  sulphuric  acid. 

92.  A  piece  of  calcium  chloride  becomes  moist  after  pro- 
longed exposure  to  the  air.    A  clear  crystal  of  sodium  sul- 
phate loses  its  transparency  and  crumbles  to  powder  after 
a  similar  exposure.    Explain  the  principle  underlying  these 
facts,  and  define  the  terms  used  to  characterize  the  proper- 
ties illustrated  by  them. 

93.  Calculate  the  approximate  weight  in  grams  of  1 1.  of 
each  of  the  following  gases:  HC1,  C12,  HI,  NH3. 

94.  How  may  CO2  be  prepared  ?   Through  what  cycle  does 
carbon  pass  in  animal  and  vegetable  life? 


94  REVIEW  QUESTIONS  AXD  PROBLEMS 

95.  Define  distillation,  filtrate,  titration,  standard  solu- 
tion,   catalysis,    indicator,    polymerization,   alkali,    neutral 
reaction,  halogen. 

96.  Explain  the  term  "  ion "  and  "  ionization."    What 
classes  of  substances  are  ionized  when  dissolved  in  water  ? 
By  what  are  all  such  substances  designated  ?    Define  acid 
and  base  in  terms  of  the  theory  of  electrolytic  dissociation. 

97.  Write  the  equation  for  preparing  hydrofluoric  acid 
and  explain  the  process  of  etching  on  glass. 

98.  Give  a  brief  account  of  the  discovery  of  any  one  of 
the  chemical  elements,  including  the  name  of  the  discoverer 
and  the  approximate  date  and  conditions  of  discovery. 

99.  What  is  the  formula  for  white  arsenic  ?   What  com- 
pound of  arsenic  is  formed  when  a  solution  of  the  substance 
is  brought  together  with  zinc  and  sulphuric  acid  ?    Why  is 
the  compound  not  formed  when  hydrogen  gas  is  led  through 
the.  solution  ? 

100.  In  what  great  industry  is  calcium  phosphate  (normal) 
employed?    To  what  treatment  must  it  first  be  subjected  ? 

101.  Name  an  important  ore  of  lead.    Describe  a  method 
of  extracting  lead  from  the  ore  mentioned,  and  mention  two 
practical  uses  of  lead. 

102.  Give  a  brief  account  of  the  alkaline-earth  metals. 
Tell  how  glass  is  made  and  colored. 

103.  State  the  general  difference  between  metals  and  non- 
metals.    What  is  a  heavy  metal  ? 

104.  Is   the  process   of   oxidation  accompanied   by  the 
process  of  reduction  ?    Illustrate  by  an  equation  and  inter- 
pret.   Is  occlusion  a  chemical  or  a  physical  action  ?    State 
your  reasons. 

105.  A  gas  globe  when  full  of  air  weighed  55.06  g.,  and 
when  full  of  water  at  20°  C.  it  weighed  309.66  g.    The  air 


MISCELLANEOUS  QUESTIONS  AND  PROBLEMS      95 

•was  removed  from  the  globe  and  the  latter  carefully  weighed 
by  means  of  a  counterpoise.  The  globe  was  then  filled  with 
a  gas  at  19.8°  C.  and  761.4mm.,  when  it  weighed  .469  g. 
more  than  when  the  air  was  exhausted.  What  is  the  weight 
of  a  liter  of  this  gas  under  standard  conditions  ? 

106.  How  many  cubic  centimeters  of  water  will  have  to 
be  added  to  10  g.  of  H2S04  to  yield  a  10  per  cent  solution 
of  the  acid? 

107.  What  is  the  heat  of  formation  of  sulphuric  acid 
from  its  elements  in  a  dilute  aqueous  solution  ? 

108.  Calculate    the    percentage    composition    of    garnet 
(<VV'(Si°4)i);  of  mica  (KH2Al8(Si04)8). 

109.  How  much  does  a  mole  of  sulphuric  acid  weigh  ?  of 
sodium  chloride  ?  of  ammonium  nitrate  ? 

110.  A  compound  of  hydrogen  and  carbon  of  exactly  the 
same  percentage  composition  has  the  gas  density  of  39. 
What  is  its  formula? 

111.  In  the  preparation  of  phosphine  what  gases  may 
take  the  place  of  hydrogen  ? 

112.  What  is  a  mineral?   Are  the  following  substances 
minerals :  quartz,  water,  granite,  mercury,  soil,  coal  oil  ? 

113.  What  other  elements  besides  aluminum  act  either 
as  acid  formers  or  as  base  formers  ? 

114.  What  substances  must  be  avoided  when  galvanized- 
iron  vessels  are  in  use  ? 

115.  Why  is  nitric  acid  a  better  solvent  for  Hg,  Cu,  and 
Ag  than  hydrochloric  or  sulphuric  acid  ? 

116.  A  silver  dollar  contains  10  per  cent  alloy  and  weighs 
26.5  g.    How  much  is  the  silver  in  it  worth  ?    How  could 
you  separate  it  from  the  copper  ? 

117.  Prove  that  the  phosphorus  molecule  has  4  atoms. 


96  REVIEW  QUESTIONS  AND  PROBLEMS 

118.  Reduce    the   following    to    the    Fahrenheit    scale: 
(«)  +  3o°C.;     (&)  +89°C.;    (c)  -  40°  C. ;    (d)  -  50°  C. ; 
(«)  +  104°C. 

119.  Reduce    the    following    to    the    centigrade    scale: 
(a)  38°  F.;  (ft)  120°  F.;  (c)  -  64°  F.;  (rf)  -30°F.;  (e)  0°F.; 
(/)  -  40°  F. 

120.  Outline  the  contact  and  the  lead-chamber  processes 
of  manufacturing  H2S04,  and  compare  them  as  to  efficacy. 

121.  Prepare  a,  table  of  the  halogens  according  to  the 
following  form: 

1.  Element. 

2.  Atomic  weight. 

3.  Compounds  found  in  nature  (formulas). 

4.  Equations  for  the  preparation  of  the  element. 

5.  Physical  properties. 

6.  Chemical  properties. 

7.  Relative  replacing  power. 

8.  Equations  for  the  preparation  of  the  hydrogen 

compound. 

9.  Stability  of  the  hydrogen  compound. 

122.  What  are  the  speeds  of  transpiration  of  ammonia 
and  nitrogen  ? 

123.  Name  three  substances  —  one  gas,  one  liquid,  and  one 
solid  —  that  are  used  for  disinfecting  and  that  have  bleach- 
ing properties.    Explain  the  action  of  each  in  bleaching. 
State  the  advantage  of  formaldehyde  for  fumigation. 

124.  In  what  liquid  is  sodium  usually  kept  ?  How  are  red 
and  yellow  phosphorus  usually  kept  ?    Explain. 

125.  Give  Avogadro's  Law  and  find  how  many  cubic  feet 
of  CO  are  represented  in  the  following  reaction  if  there 
are  represented  10  cu.  ft.  of  C02,  all  volumes  at  the  same 
temperature  and  pressure, 


PROBLEMS  97 

CHAPTER  XXVI 

PROBLEMS  ON  MEASUREMENT,  TEMPERATURE, 
WEIGHT,  AND  DENSITY 

A.  MEASUREMENT 

1.  Find  the  number  of  liters  in   a   cubic  meter;  the 
number  of  cubic  millimeters. 

2.  How  many  millimeters  in  («)  16km.?  (b)  21Hm.? 
(c)  26.9m.?  (d)  66.92dm.?  (e)  108.2cm.? 

3.  How  many  feet  in  62.14  m.  ?  in  390  m.  ? 

4.  Convert  43  in.  into  (a)  decimeters ;  (6)  hectometers ; 
(<;)  kilometers  ;  (</)  centimeters  ;  (e)  millimeters. 

5.  Calculate  the  number  of  liters  necessary  to  fill  with 
water  a  tank  21  x  60  x  8  ft.  in  dimension. 

6.  Required  the  number  of  square  millimeters,  square 
centimeters,  square  decimeters,  contained  in  the  top  of  a 
flat  desk  measuring  1  in.  20  cm.  by  80  cm. 

7.  How  many  miles  in  15km.? 

8.  A  room  20  m.  x  50  m.  x  3m.  is  filled  with  air  under 
standard  conditions.    How  many  liters   are  there  ?    How 
much  does  it  weigh  in  kilograms  ? 

9.  A  woodpile  containing  1500  m.8  is  12  m.  long  and 
12  m.  wide.    How  high  is  it  ? 

10.  What   is    the   capacity  of  a  tank  in   liters  that  is 
4  m.  x  9  m.  x  8  m.  in  dimension  ? 

11.  What  is  the  radius  in  centimeters  of  a  sphere  whose 
volume  is  measured  by  6  1.  of  water  ? 

12.  How  deep  must  a  cistern  be  to  hold  80001.,  if  the 
bottom    lias  a   radius  of  1.75m.?    How  deep  if  it  has  a 
square  bottom  3m.  on  a  side? 


98  REVIEW  QUESTIONS  AND  PROBLEMS 

13.  A  rectangular  scow  40m.  long  and  7m.  wide  draws 
1  in.  of  water  when  empty  and  3  in.  when  loaded ;  find  in 
kilograms  the  weight  of  the  load. 

14.  How  many  liters  will  a  cylindrical  gasometer  1  in. 
across  and  15  m.  high  hold  ? 

15.  A  pressure  of  1000  Ib.  per  square  inch  is  how  many 
kilograms  per  square  millimeter  ? 

B.  TEMPERATURE 

1.  Convert  into  the  centigrade  scale : 
(a)  36°  R.;  (b)  28°  R.;  (c)  76°  R. 

2.  Convert  into  the  Reaumur  scale : 
0)90°C.;  (7»)15°C.;  (c)  55°C.;  (d)  30°  C. 

3.  Convert  into  the  Fahrenheit  scale : 

(a)  52° R.;  (b)  76° R.;  (c)  6.7° R.;  (d)  25° R. 

4.  Convert  into  the  Reaumur  scale: 

(a)  48°  F.;  (b)  129°  F.;  (c)  210°  F.;  (d)  -  30°  F. 

5.  Convert  into  the  centigrade  scale : 

(a)  207° F.;  (ft)  180° F.;  (c)  0°F.;  (d)  -30°F. 

6.  Convert  into  the  Fahrenheit  scale : 

(a)  643° C.;  (b)  972° C.;  (c)  -40°C.;  (rf)  2500° C. 

7.  Convert  into  the  absolute  scale : 

(a)  8°C.;  (b)  40°C.;  (c)  80°C.;  (d)  2000°F.;  (e)  - 37°F. 

8.  Convert  into  centigrade,  Reaumur,  and  Fahrenheit 

scales : 
(a)  400°  and  (V)  267°  absolute  scale. 

C.  WEIGHT  AND  DENSITY 

1.  How  much  space  will  4320  g.  of  water  occupy  ? 

2.  What  is  the  weight  of  water  in  a  tank   20  cm.  x 
31cm.  x  92cm.? 

3.  A  mass  of  63  g.  is  divided  into  pills  7  in  number. 
What  is  the  weight  of  each  ? 


I'KOIJLKMS  99 

4.  If  a  liter  of  Hg.  weighs  13  kg.  598  g.,  find  the  weight 
in  kilograms  of  4.2  1. 

5.  A  cubical  block  of  wood  2  cm.  on  a  side  weighs  5  g. 
How  far  will  it  sink  in  alcohol  of  specific  gravity  .8  ? 

6.  If  the  density  of  brass  is  8.5,  what  will  be  the  weight 
in  air  of  a  mass  of  brass  which  weighs  in  vacua  500  g.? 

7.  A  liter  flask  weighs  25  g.    When  filled  with  a  mixture 
of  alcohol  and  water  it  weighs  867  g.     How  many  cubic 
centimeters  of  each  in  the  flask  ? 

8.  A  piece  of  cork  floats  on  ether  with  12  cc.  exposed. 
What  is  the  entire  volume  of  the  cork? 

9.  The  pressure  of  the  air  will  hold  water  30  ft.  high  in 
a  vacuum.    How  high  will  it  hold  mercury  ? 

10.  If  a  pint  of  water  weighs  exactly  a  pound,  how  many 
cubic  inches  would  it  contain  ? 

11.  A  lump  of  metal  weighs  a  ton.    Its  weight  in  water 
is  1500  Ib.    What  is  its  specific  gravity  ? 

12.  Find  the  mass  of  50  cc.  of  benzine  if  its  density  =  0.85. 

13.  A  piece  of  lead  weighed  39.9  g.  in  air  and  36.368  g. 
in  water.    What  is  the  specific  gravity  of  lead  ? 

14.  Find  the  volume  of  1000  g.  of  sea  water. 

15.  Find  the  specific  gravity  of  alcohol  from  the  follow- 
ing data : 

1.  Weight  of  specific-gravity  bottle  empty,  20.3920  g. 

2.  Weight  of  specific-gravity  bottle  filled  with  water, 

70.3412  g. 

3.  Weight  of  specific-gravity  bottle  filled  with  alcohol, 

61.6515  g. 

16.  A  piece  of  lead  weighs  50  g.  in  air,  and  when  sus- 
pended in  a  liquid  whose  specific  gravity  is  1.2  it  weighs 
44.69.    Determine  the  specific  gravity  of  lead. 


100          REVIEW  QUESTIONS  AND  PROBLEMS 

17.  If  sulphuric  acid  has  a  specific  gravity  of  1.84,  how 
many  cubic  centimeters  of  it  weighs  80  g.  ? 

18.  Nitric  acid  is  1.52  times  as  heavy  as  water.   What  is 
the  weight  of  3  1.  of  the  acid  ? 

19.  A  balloon  contains  1000  cu.  m.  of  a  gas  whose  density 
is  0.000092  g.  per  cubic  centimeter.    Taking  the  density  of 
air  as  0.0003  g.  per  cubic  centimeter,  calculate  the  total 
weight  which  the  balloon  will  lift. 

20.  A     block     of    wood    having    a    cross    section    of 
5  cm.  x  4  cm.  x  3  cm.  floats  in  water  when  immersed  to  a 
depth  of  2.5  cm.   What  mass  of  lead  on  the  top  would  be 
sufficient  to  cause  complete  immersion  of  the  block  ? 

21.  A  piece  of  metal  weighs  50  g.  in  air,  and  when  sus- 
pended in  a  liquid  whose  specific  gravity  is  1.2  it  weighs 
44.6  g.   What  is  its  specific  gravity  and  what  metal  is  it  ? 

22.  What   is   the  weight   of  ammonia  and  of  chlorine 
necessary  to  produce  1 1.  of  nitrogen  ? 

23.  Calculate  the  specific  heat  of  iron  from  the  follow- 
ing data: 

1.  Weight  of  iron  used,  100  g. 

2.  Weight  of  ice  melted,  14.35  g. 

3.  Temperature  of  the  iron  at  the  beginning  of  the 

operation,  100°  C. 

4.  Latent  heat  of  water,  80. 

24.  How  many  cubic  centimeters  of  a  liquid  of  specific 
gravity  1.4  must  be  mixed  with  1 1.  of  a  liquid  of  specific 
gravity  .8  to  make  a  mixture  of  specific  gravity  1.2  ? 

25.  A  capillary  glass  tube  weighs  .2  g.    A  thread  of  mer- 
cury 12  cm.  long  is  drawn  into  the  tube,  when  it  is  found  to 
weigh  .7  g.    Find  the  diameter  of  the  capillary  tube. 

26.  Find  the  length  of  an  iron  rod  2  cm.  in  diameter 
that  weighs  1  kg. 


PROBLEMS  101 

27.  If  gold  were  bought  in  Alaska  at  a  certain  price  per 
ounce,  and  sold  in  Mexico  at  the  same  price,  would  there  be 
a  gain  or  loss,  transportation  charges  not  being  considered  ? 

28.  A  quantity  of  silver  when  placed  in  one  pan  of  an 
untrue  balance  appeared  to  weigh  5  gm.,  but  when  placed 
in  the  other  pan  6  gm.   What  is  the  true  mass  of  the  silver  ? 


APPENDIX 


CHAPTER  XXVII 

I.   PHYSICAL  CONSTANTS  OF  THE  IMPORTANT 
ELEMENTS1 


ELEMENT 

SYMBOL 

ATOMIC 
WEIGHTS 

VALENCE 

SPECIFIC 
GRAVITY 

MEI.T- 

PolXT 

BOIL- 
ING 

POINT 

Ap- 

proxi- 
mate 

Exact 

Water 

Air 

Aluminum  .  . 

Al 

27. 

27.1 

III 

2.6 

657. 

1500. 

Antimony   .  . 

si, 

120. 

120.2 

6.6 

630. 

1500. 

Argon   

A 

40. 

39.9 

1.38 

-188. 

-186. 

Arsenic   

Aa 

75. 

75. 

III.V 

5.7 

360. 

Barium   .... 

Ba 

137. 

137.4 

II 

3.8 

850. 

950. 

Bismuth.  .  .  . 

Bi 

208. 

208. 

III.V 

9.7 

269. 

1435. 

Boron  

B 

11. 

11. 

III 

2.6 

infus. 

3500. 

Bromine.  .  .  . 

Bi 

80. 

79.96 

I 

3.1 

-73 

59. 

Cadmium  .  .  . 

Cd 

112. 

112.4 

II 

8.6 

322. 

778. 

Calcium  .... 

Ca 

40. 

40.1 

II 

15 

800. 

Carbon  

C 

12. 

12. 

IV 

1.7-2.1 

subl. 

3500. 

Chlorine.  .  .  . 

n 

35.5 

35.45 

I 

2.49 

-102. 

-33.6 

Chromium  .  . 

Or 

52. 

52.1 

II,  III,  VI 

6.9 

1515. 

Cobalt  

Co 

59. 

59. 

II 

8.7 

1530. 

Copper  

Oa 

63.6 

63.6 

1,11 

8.9 

1065. 

2100. 

Fluorine.  .  .  . 

F 

19. 

19. 

I 

1.31 

-223. 

-187. 

Gold  

Au 

197. 

197.2 

I,  III 

19.3 

1065. 

Helium  

Be 

4. 

4. 

0.13 

-271. 

-267. 

Hydrogen.  .  . 

11 

\ 

1.008 

I 

0.07 

-256.5 

-2525 

Iodine    

I 

127'. 

126.9 

I 

4.9 

114. 

184. 

Iron  

Fe 

56. 

58.9 

n,  in 

7.8 

1950. 

Lead 

Pb 

207 

2069 

II   IV 

11.3 

327 

1400. 

Lithium  .... 

U 

7. 

7.03 

i 

059 

186. 

1400. 

Magnesium    . 

Mg 

24.3 

24.3 

ii 

1.7 

632. 

1100. 

Manganese.  . 

Mn 

55. 

55. 

II,  IV 

7.4 

1245. 

Mercury  .... 

Kg 

200. 

200. 

1,11 

13.6 

-38.8 

357. 

Nickel  

Ni 

58.7 

58.7 

h 

8.7 

1484. 

Nitrogen   .  .  . 

N 

14. 

III.V 

0.96 

-210. 

-195. 

Oxygen  

o 

ie!oo 

ii 

1.10 

-230. 

-  182. 

Phosphorus  . 
Platinum  .  .  . 

p 

rt 

31. 
195. 

31. 

194.8 

IILV 
IV 

1.8 
21.5 

44.2 
1710. 

290. 

Potassium  .  . 

K 

39. 

39.1 

I 

0.87 

625 

757. 

Silicon  

Si 

28. 

28.4 

IV 

2.0 

3500. 

Silver  

Ag 

108. 

107.9 

I 

105 

961. 

2050. 

Sodium    .... 

Na 

23.05 

I 

057 

97.6 

877. 

Strontium   .  . 

Sr 

8?! 

87.6 

II 

25 

900. 

Sulphur  .... 
Tin  

S 
Sn 

33. 
119. 

32.06 
119.0 

II,  IV,  VI 

h,iv 

2.0 
73 

1145 
232. 

444.6 
1600. 

Zinc  

•/.n 

65. 

65.4 

ii 

7.1 

419. 

918. 

1  This  table  will  be  found  in  the  text  of  Brownlee  and  others,  and  is  used  by 
their  permission. 


104          REVIEW  QUESTIONS  AND  PROBLEMS 

II.  WEIGHTS  AND  MEASURES 

LENGTH 


1  millimeter  (mm.) 
1  centimeter  (cm.) 
1  decimeter  (dm.) 
1  meter  (m.) 
1  kilometer  (km.) 

=  10  mm. 
=  10  cm. 
=  10  dm. 
=  1000  in. 

=    0.03937  inch 
=    0.3937    inch 
=    3.937      inches 
=  39.37        inches 
=    0.6214    mile 

VOLUME 

1  cubic  centimeter  (ccm.)  =    0.06103  cubic  inch 

1  cubic  decimeter       =  1000  ccm.  =  61.03        cubic  inches 
1  liter  (1.)  =1000ccm.  =    1.057      quarts 

1  cubic  meter  =10001.        =35.32        cubic  feet 


WEIGHT 

1  milligram  (mg.)  =    0.0154  grain 

1  gram  (g.)  =  1000  mg.  =  15.432  grains 

1  kilogram  (kilo),  kg.  =  1000  g.  =    2.2046  pounds  av. 


III.  TABLE  OF  METRIC  TRANSFORMATION 


To  <:n.\  M;  i: 

Inches  to  centimeters  . 
Centimeters  to  inches  . 


MULTIPLY  BY 
.       2.54 
0.3937 


Cubic  inches  to  cubic  centimeters  .    .    .« 16.387 

Cubic  centimeters  to  cubic  inches 0.061 

Ounces  to  grams  (avoirdupois) 28.35 

Grams  to  ounces  (avoirdupois) 0.0353 

Grains  to  grams 0.0648 

Grams  to  grains 15.43 


APPENDIX 


105 


IV.    WEIGHT  OF  ONE  LITER  OF  VARIOUS  GASES 

MEASURED  UNDER  STANDARD 

CONDITIONS 


Air  

.    .     1.2023 

Oxygen 

1  430 

Ammonia    .... 

.    .     0.7(il7 

Hydrogen  

.     0.08984 

Carbon  dioxide  .    . 

.    .     1.  '.IIJ41 

Hydrosulphuric  acid 

.     1.5211 

Carbon  monoxide  . 
Chlorine      .... 
Cyanogen    .    '.    .    . 

.    .     1.251 
.    .     3.1650 
.    .     2.322 

Methane    .    .    .    .    . 
Nitric  oxide  .... 
Nitrogen 

.     0.7157 

.    i.slto 

1  2501 

Ethylene     .... 

.    .     1.252 

Nitrons  oxide    .    .    . 

.     1.9677 

Hydrazoic  acid  .    . 
Hydrocyanic  acid  . 

.    .     1.920 
.     1.2036 

Sulphur  dioxide    .    . 
Steam    . 

.     2.8596 
0.805 

V.   PHYSICAL  FORMULAS 
TEMPERATURE 


BOYLE'S  AND  CHARLES'S  LAWS  COMBINED 


(«)r  = 


-a) 


760°  [1  +  (.003660] 


T'P 


VI.  SPECIFIC  GRAVITIES 


Brass     

8.4 

Nitric  acid 

1  56 

Cork  

0.25 

Silver  

.    .     10.5 

Coal  

1.8 

Sulphuric  acid     .     . 

.    .       1.84 

Gold  

19.8 

Tin  , 

.    .       7.3 

Hydrochloric  acid     .     .     . 

1.22 

Water  (distilli-d)     . 

.    .       1. 

Iron  

7.8 

Water  (sea)     ... 

.    .       1.025 

Kcrosr-iH'  

0.8 

Water  (ice)     .    .    .    , 

0.92 

Lead     

11.3 

Zinc     

7.1 

106 


REVIEW  QUESTIONS  AND  PROBLEMS 


S3 


2      3 


UNIVERSITY  OF  CALIFORNIA  AT  LOS  ANGELES 
THE  UNIVERSITY  LIBRARY 

This  book  is  DUE  on  the  last  date  stamped  below 

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0V  16  1939 
w     3  1940 


JAN  3  0  1947 
APR  22 


194- 


194C 


MAR  1  7  1943 

**&  1  7  1Q49 

Form  L-9-15m-3,'34 


FEBl 

-RHTDCOLLIB. 


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